VST Settings are not preserved properly

Operating System Info

Windows 10

Other OS

No response

OBS Studio Version

29.0.0

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/YYZDFex1Q3vJy7Dy

OBS Studio Crash Log URL

No response

Expected Behavior

When setting some values inside a vst plugin and closing OBS, the next time OBS is opened the vst plugin should be with the values last set.

Current Behavior

Everything works as expected until I make an update to my vst plugin.
If updated, the plugin won't restore the values last saved.

Steps to Reproduce

1. Install Youlean Loudness Meter 2 VST plugin latest release version 2.4.3 (or any other plugin)
2. Open the plugin in OBS and set some values
3. Close OBS
4. Install Youlean Loudness Meter 2 VST plugin from latest beta version 2.5.2
5. Open OBS
6. See that the setting you made last, were not preserved
   ...

Anything else we should know?

This is happening due the fact that you use MD5 in order to verify if the plugin should get it's chunk.
So for any plugin update, plugin's session information is lost. That is not how it should behave.
Proper way to do it in VST is to compare the uniqueID member of the AEffect instance.

Start by locating OBS Studio's VST state handling and the MD5 verification mentioned in the issue. Reproduce the settings loss by updating a VST plugin, then inspect how the plugin's uniqueID is available through AEffect. Done means settings remain preserved across compatible plugin updates, with the existing reproduction behavior verified.