Update class.list.php

Feature: canned response rendered using select2

Address Security Issues On #4331

issue: Auto-Assignment Log

issue: Ticket Lock On Disable

issue: User Import No Email

This addresses an issue where disabling Ticket Locks but setting a time
for the Lock Timeout will always throw a "lock required" error. This adds
a check to see if locks are enabled AND there is a time set. If locks are
disabled it will not throw the error.

This addresses issue 4329 where you can import a User with no email
address via CSV file. Once the User is added and you try to update them
with an email address it fails due to no default email. This updates the
check for email address from `!isset()` to `empty()` which will correctly
check for empty string.

issue: CLI Deploy Missing Bootstrap

issue: Language Pack Locale Mismatch

This addresses an issue where osTicket did not ensure associated items exist
before saving to the database. This also addresses an issue where the Parent
Topic error was not displayed on page.

It may be possible to steal or manipulate customer session and cookies,
which might be used to impersonate a legitimate user, allowing the hacker to
view or alter user records, and to perform transactions as that user.
Sanitation of hazardous characters was not performed correctly on user
input.

osTicket did not properly sanitize array values in `Format::htmlchars()`.
Some values in the Admin Interface were not properly sanitized and returned
to the response.

This addresses issue 4322 where deploying via CLI is missing
`bootstrap.php`. This is due to the `get_include_dir()` function that
tries to include a file from the destination which doesn’t exist yet,
causing a fatal error. This updates the function to use `$this->source`
instead of `$this->destination` to correctly find and include
`bootstrap.php`.

This addresses issue 4325 where the Language Pack Locales are mismatched.
The Locale for the first language is displayed on the second language,
etc. This updates the `$manifest` variable to be set before we display
data so the correct `MANIFEST` file is included and all language data is
displayed correctly.

This addresses an issue on the Forums where the Auto-Assignment Thread
Event (configurable via Help Topic) uses the Email of the User rather than
the User’s Name. This adds the correct function to retrieve the User’s
Name if the User has an Account.

issue: Section Break Hint

oops: Prevent Account Takeover

orm: queryset: Fix circular reference error

xss: Prevent Agent Directory XSS

Check permissions before displaying Close Task

format: Fix Vimeo iFrames

issue: Fix imap_open Disable Authenticator

oops: Fix randNumber()

issue: AJAX Reflected XSS

issue: Prevent Click Jacking

issue: Information Page Performance

Some fix for PHP 7,2 https://github.com/osTicket/osTicket/issues/4237

This addresses an issue on the forums where the query to determine the
size of the `file_chunk` table is making the page load really slow for
people with large tables. This updates the query to improve the
performance of the page load time.

This addresses a vulnerability where there was no `X-Frame-Options` header
which could potentially allow click jacking. This adds the
`X-Frame-Options: SAMEORIGIN` header so it will remove any chance of click
jacking. According to Mozilla Developer Docs:
```
SAMEORIGIN
The page can only be displayed in a frame on the same origin as the page
itself.
```

issue: Files - deleteOrphans()

This addresses the issue where files were being deleted before being sent
out in Agent responses. This was due to a bug in the query that gets the
orphaned files. This query was getting files created within the last 24
hours not after the last 24 hours. The query also had another bug that
would use the time from PHP instead of MySQL which could cause issues.
This updates the query as per @greezybacon's suggestions to delete
orphaned files that were created more than 24 hours ago.

This fixes an error where the ModelInstanceManager maintained a reference to
the QuerySet instance, and the QuerySet instance managed a reference to the
ModelInstanceManager instance (if it's the iterator for the query). Because
of the circular reference, if the iterator is not exhausted, then the
resource is not closed and the query remains open. This wastes memory and
prevents some other queries from running after such a situation happens.

This addresses the issue by removing the circular reference between the
QuerySet and the ModelInstanceManager.

issue: Outlook _MailEndCompose

upgrader: Flush Cache On Upgrade

issue: Org. User Account Status

This addresses an issue where the Upgrader will sometimes use an outdated
cached object and throw an error. This adds a the function to clear the
Model Cache every time the Upgrader runs an Upgrade Patch to get fresh
objects.

This addresses an issue where the User’s account status is always 'Active'
in the Organization list no matter what their actual status is. This adds the
account status to the user query which adds the correct status to the Users’
account.

This addresses an issue where Outlook adds weird (and seemingly random)
_MailEndCompose tags to the email body which turns unwanted content into
links. This adds the _MailEndCompose tag to Format::sanitize() so it
will be removed from the email body.