Add ConfigKnobShim GoogleTests

[VivianNK]

Description

Original PR: https://github.com/microsoft/mu_feature_config/pull/200

Google Tests for ConfigKnobShimDxeLib and ConfigKnobShimPeiLib ConfigKnobShimPeiLib is consuming the PPI mock from mu_basecore (https://github.com/microsoft/mu_basecore/pull/579), so merging this is pending the mu_basecore PR being merged. Pipelines will fail in the meantime.

• [ ] Impacts functionality?
  • Functionality - Does the change ultimately impact how firmware functions?
  • Examples: Add a new library, publish a new PPI, update an algorithm, ...
• [ ] Impacts security?
  • Security - Does the change have a direct security impact on an application, flow, or firmware?
  • Examples: Crypto algorithm change, buffer overflow fix, parameter validation improvement, ...
• [ ] Breaking change?
  • Breaking change - Will anyone consuming this change experience a break in build or boot behavior?
  • Examples: Add a new library class, move a module to a different repo, call a function in a new library class in a pre-existing module, ...
• [x ] Includes tests?
  • Tests - Does the change include any explicit test code?
  • Examples: Unit tests, integration tests, robot tests, ...
• [ ] Includes documentation?
  • Documentation - Does the change contain explicit documentation additions outside direct code modifications (and comments)?
  • Examples: Update readme file, add feature readme file, link to documentation on an a separate Web page, ...

How This Was Tested

Ran the tests using stuart_ci_build.

Integration Instructions

N/A

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (6666855) 27.39% compared to head (9812a26) 27.39%.

:exclamation: Current head 9812a26 differs from pull request most recent head a9fad3e. Consider uploading reports for the commit a9fad3e to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #254 +/- ## ======================================= Coverage 27.39% 27.39% ======================================= Files 16 16 Lines 4552 4552 ======================================= Hits 1247 1247 Misses 3305 3305 ``` | [Flag](https://app.codecov.io/gh/microsoft/mu_feature_config/pull/254/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=microsoft) | Coverage Δ | | |---|---|---| | [Linux](https://app.codecov.io/gh/microsoft/mu_feature_config/pull/254/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=microsoft) | `27.39% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=microsoft#carryforward-flags-in-the-pull-request-comment) to find out more.

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