Bug: Extracting the release archive into plugins does not automatically owrk

[Ilidur]

Steps to reproduce the behavior

1. unarchive plugin into /plugins
2. enable plugin
3. see error

This plugin failed to start. unable to generate webapp bundle: focalboard: unable to copy webapp bundle directory: focalboard: stat plugins/focalboard/webapp/dist: no such file or directory

4. rename folder from boards to focalboard
5. enable plugin
6. all works

Expected behavior

Plugin works after extracting archive.

Screenshots (optional)

If applicable, add screenshots or a screen recording to elaborate on the problem.

Edition and Platform

• Edition: Mattermost Boards (plugin)
• Version: 9.1.1
• Browser and OS: Linux in docker

Additional context (optional)

[tmotyl]

related or duplicated #24