I tried to check my wallet plugin folder and I found it in this path C:\Program Files\Electrum\electrum\plugins
So you can't find the plugin folder in user/username/AppData/roaming or even in the temp folder, the temp folder is used only for temporarily write data comes from the running software/app that is why it always created new data folder every time you open the electrum.

This is the right path C:\Program Files\Electrum\electrum\plugins