Generate a Property Sheet for Windows plugins

[stuartmorgan-g]

Description

Generates a Property Sheet for Windows builds containing link and include path
information for any included plugins. This allows automating part of the process
of integrating plugins into the build that is currently manual.

To support this change, refactored msbuild_utils into a PropertySheet class so that
it can be used to make different property sheets.

Related Issues

#32719

Tests

I added the following tests:

• Tests of the new PropertySheet class
• Tests that the new property sheet is created as expected by the plugin codepaths
• Tests that the plugin registrant is generated on Windows (not directly related to
  this change, but I noticed they are missing, and it's in the same domain).

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]). This will ensure a smooth and quick review process.

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I signed the CLA.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I updated/added relevant documentation (doc comments with ///).
• All existing and new tests are passing.
• The analyzer (flutter analyze --flutter-repo) does not report any problems on my PR.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Did any tests fail when you ran them? Please read Handling breaking changes.

• No, no existing tests failed, so this is not a breaking change.

[jonahwilliams]

LGTM