Fix unit test execution

[zvecr]

Description

Replaces #23034.

Fixes running unit tests located outside /tests folder. Aligns test names with keyboard compilation, / instead of :.

• Partial revert of Improve test invocation, fix Retro Shift bugs, and add Auto+Retro Shift test cases #15889
• Running make test:auto_shift will run all Auto Shift tests
• 15889 reverted the previous "fix" that was included within Unicode, Unicodemap and UCIS refactor #21659
  • Fixed a small bug with test matching due to how findstring works (eg. make test:unicode builds every test suite starting with unicode instead of just the one named unicode)
• Partial matches will only be currently supported via future CLI changes

Adds make list-tests to make test name discovery a little eaiser.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).