Regression in SourceLink Url generation when metadata is missing

[MattGal]

@adiaaida FYI if you want to handle it, otherwise I think Eric's suggestion will work (setting up a thing to test that)

#7844 introduced the change, but it's evidently possible for https://github.com/dotnet/arcade/blob/main/src/Microsoft.DotNet.Arcade.Sdk/tools/RepositoryInfo.targets#L76 a missing ScmRepositoryUrl metadata item on SourceRoot.

[MattGal]

I set up a quick repro, and thanks to some quick help from the Rainer on the MSBuild team was able to get this PR created:
https://github.com/dotnet/arcade/pull/7852/files

[michellemcdaniel]

MSBuild is so hard! Sorry about the mess up. Matt, can you also port this to release/6.0 once it goes into main?

[MattGal]

MSBuild is so hard! Sorry about the mess up. Matt, can you also port this to release/6.0 once it goes into main?

Created #7854

[ericstj]

MSBuild is so hard! Sorry about the mess up

No worries, I've hit this exact same bug before.

[MattGal]

This fix worked locally in my "artificial" setup but not in practice. back to WIP, will handle it as fast as I can.

[michellemcdaniel]

:(

[MattGal]

:(

Sorry I just only fixed one location, the new one fixes both and definitely works on the arcade-validation build.

[MattGal]

I have shepherded the complete fix through on both main and release/6.0 and things look good through publishing on main. Release/6.0 doesn't seem to be set up to automatically trigger post-merge so I manually kicked it and mentioned that to @epananth