BLT-5215: UserConfig Class not found

[aneek]

Describe the bug
Certain libraries for example shelane/toggle-modules unable to find the Acquia\Blt\Robo\Common\UserConfig class.

To Reproduce
Steps to reproduce the behavior, ideally starting from a fresh install of BLT:

1. Clone BLT repo.
2. Unable to find UserConfig.php inside src/Blt/Robo/Common directory. It was present on or before version 13.7.0.

Expected behavior
Documentation explaning how to use UserConfig class.

[joegl]

The UserConfig class appears to have been removed in 13.7.1. I'm currently looking for release notes on how we should replace our implementations of UserConfig.

I don't see anything in the release notes here: https://github.com/acquia/blt/releases/tag/13.7.1

• The 4 PR's linked here don't include the removal of the UserConfig class.
• But if you compare 13.7.0 to 13.7.1 you can see it was removed.

[joegl]

I found the PR that removed the file: #4643

It appears to be part of removing telemetry from BLT. I'm not sure why it wasn't included in the release notes.

[danepowell]

We removed telemetry in #4643. We removed UserConfig along with it since the UserConfig was only used to store telemetry preferences and we had no awareness of anyone extending the UserConfig class.

The UserConfig is basically just a wrapper around a Json file, it should be easy to replicate independently if you need it. You really just need the constructor and save() method.