[UH] GD Gif Animations 2.3.7

Optimized the code.
The constant checks for the existence of gifsicle have been removed, which led to too long php requests, now it checks only on the plugins page.
XenForo 2.2.* is no longer supported.

Fixed a minor issue with checking the avatar size.

The setting did not work when the installation of the utility was falsely triggered.
Fixed the issue of false positive validation during installation on centos.
Fixed a problem when determining the size of the avatar, thanks @rdn (https://xenforo.com/community/threads/uh-gd-gif-animations.230199/post-1745075).

Fixed an issue with adding video/audio files.
Thanks @rdn (https://xenforo.com/community/threads/uh-gd-gif-animations.230199/post-1744728)

Added compatibility of the forum version 2.2.6 and higher. The addon now works on both 2.2.* and 2.3.*
The gifsicle utility installation check is enabled. Verification is also enabled on a server running the Windows operating system.

New addon settings have been added: in the attachment block in the message, play the animation of GIF images. This can be disabled on slow servers. Added the ability to remove a notification about a missing gifsicle if the utility is installed, but the addon still shows the notification, possibly with incorrect verification.

The addon settings are displayed in a separate group.
Optimized the code