Fix incompatibility between shared .projitems and UpdateXlfOnBuild

[nguerrera]

• Shared items from .projitems projects with HasSharedItems=true property get their Link metadata assigned by AssignLinkMetadata target
• XliffTasks needs this Link metadata to work correctly
• XliffTasks had no manifested dependency on AssignLinkMetadata
• Without UpdateXlfOnBuild set, XliffTasks got lucky and ran after AssignLinkMetadata
• With UpdateXlfOnBuild, XliffTasks registers itself to do some work before BeforeBuild which causes it to run before AssignLinkMetadata, which breaks it.

The fix here is to manifest a dependency on AssignLinkMetadata.

To double check:

• The right tests are in and the right validation has happened. Guidance: https://github.com/dotnet/arcade/blob/main/Documentation/Validation.md

No, I have done only manual testing. Please take over this PR from me and test as appropriate. 😆

Here is the minimal repro that I used to debug this: nguerrera/repros@392d4bb

Please make this into a test that can run automatically to prevent regression. When you run repro.cmd, it will build with and without UpdateXlfOnBuild and put binlogs and ildasmed fr resource dlls in tmp/with_update. Diff the ildasm output and you will see that without this fix, there is a bad resource name used:

$ diff tmp\without_update\XliffResourceNames.il tmp\with_update\XliffResourceNames.il | grep .resources
< .mresource public XliffResourceNames.Test.fr.resources
> .mresource public XliffResourceNames.D_.Src.repros.OutsideXliffResourceNames.Test.fr.resources
<   // WARNING: managed resource file XliffResourceNames.Test.fr.resources created
>   // WARNING: managed resource file XliffResourceNames.D_.Src.repros.OutsideXliffResourceNames.Test.fr.resources created``

Fix #15296

[nguerrera]

@jaredpar

[jaredpar]

Awesome thank you!!