Fix MdeModulePkg host test (microsoft#357)

# Preface

Please ensure you have read the [contribution
docs](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md) prior
to submitting the pull request. In particular,
[pull request
guidelines](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md#pull-request-best-practices).

## Description

This change fixed a host unit test break introduced in
microsoft#354.

It should be removed when resolving this issue
microsoft#356.

For each item, place an "x" in between `[` and `]` if true. Example:
`[x]`.
_(you can also check items in the GitHub UI)_

- [ ] 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

This was tested on the pipeline.

## Integration Instructions

N/A

MdeModulePkg/Test/MdeModulePkgHostTest.dsc

@@ -130,4 +130,7 @@
     <LibraryClasses>
       UefiSortLib|MdeModulePkg/Library/UefiSortLib/UefiSortLib.inf
       DevicePathLib|MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.inf
+      # MU_CHANGE [BEGIN]: Temporarily fixing a regression due to recent change in UnitTestFrameworkPkgHost.dsc.inc
+      UefiBootServicesTableLib|UnitTestFrameworkPkg/Library/UnitTestUefiBootServicesTableLib/UnitTestUefiBootServicesTableLib.inf
+      # MU_CHANGE [END]: Temporarily fixing a regression due to recent change in UnitTestFrameworkPkgHost.dsc.inc
   }