Error in PHP 8.1:

Deprecated:  strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in /Users/huongnv/Work/stable_master/moodle/lib/classes/component.php on line 1056 

Steps to replicate

1. Create a new LMS instance (if needed).
2. Make sure that you're running on PHP 8.1 or 8.2.
3. Make sure to turn on the Debugging mode.
4. Install the tool_mfa from MDL-78509 or https://github.com/catalyst/moodle-tool_mfa (I'd suggest to install it from MDL-78509).
5. Navigate to Site Administration and finish the upgrade process.
6. Run this command in the command line: rm -rf admin/tool/mfa
7. Run this command in the command line: php admin/cli/purge_caches.php
8. Navigate to Site Administration.
9. Verify the content of the page.

Expected result:

The user will see the Plugins check page saying that tool_mfa and factors are missing from disk.

Actual result:

A lot of deprecation warnings at the top of the page.