Add ThirdPartyNotice file to packages

[michael-hawker]

Describe the bug

We should add our ThirdPartyNotice.txt file to our packages as a loose file like we do with the license.

Should be here:

WindowsCommunityToolkit/build/Windows.Toolkit.Common.targets

Lines 15 to 18 in 41b0c9a

	<ItemGroup Condition="$(IsPackable)">
	<None Include="$(BuildToolsDirectory)nuget.png" Pack="true" PackagePath="\Icon.png" />
	<None Include="$(RepositoryDirectory)License.md" Pack="true" PackagePath="\" />
	</ItemGroup>

[michael-hawker]

Also noticed we're missing the last two copies of licenses in the file... 🙋‍♂️

[Nirmal4G]

We also have a ReadMe support now too. We could update each package with its own ReadMe as well. We could do this along with #4210!

[michael-hawker]

The Third Party Notice file is a legal document we just need to include. It's not something we need to put content into the readme for.

[Nirmal4G]

That's not what I meant.