Replace TestSelector with ResourceTypeSelector

[dbeatty10]

Resolves NA

Problem

The TestSelector class was introduced in #2628, but it doesn't need to offer anything differentiated anymore.

Solution

Simplify by standardizing upon the ResourceTypeSelector.

This was accomplished by:

1. replacing all instances of TestSelector with ResourceTypeSelector
2. removing the TestSelector class

Some history of the TestSelector class

To help us avoid a Chesterton's fence situation:

1. was first introduced in #2628 merged on 2020-07-20
   • contained two differentiated attributes: data and schema
   • contained a differentiated method: expand_selection
2. modified 1 day later in #2629
   • removed differentiated attributes: data and schema
3. modified 9 months later in #3235
   • removed differentiated method: expand_selection

Additional information

Doing this simple refactor makes it easy to see the root cause of the bug report in #10727.

Refactoring first will make it easier to review the code changes in #10706 (which will also resolve #10727).

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• Tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.).
• This PR includes type annotations for new and modified functions.

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the contributing guide.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.88%. Comparing base (16f5023) to head (9f65a92).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10718      +/-   ##
==========================================
- Coverage   88.88%   88.88%   -0.01%     
==========================================
  Files         180      180              
  Lines       22856    22851       -5     
==========================================
- Hits        20316    20311       -5     
  Misses       2540     2540              

Flag	Coverage Δ
integration	86.08% <100.00%> (-0.01%)	⬇️
unit	62.42% <25.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
Unit Tests	62.42% <25.00%> (-0.01%)	⬇️
Integration Tests	86.08% <100.00%> (-0.01%)	⬇️