Update SymUploader to incoporate additional params for symbol publishing

[epananth]

To double check:

• The right tests are in and and the right validation has happened. Guidance: https://github.com/dotnet/core-eng/tree/master/Documentation/Validation

Part 2 changes for issue -> #7988

This change includes additional param TreatPdbConversionIssuesAsInfo, so that we do not error out during the scenario where the symbols do not contain any .dlls during pdb conversion

For V3 this param is always going to be false since we do not do the pdb conversion for every build. Staging pipeline still uses V2 so we made this param settable in PublishSymbol.proj

[hoyosjs]

Is there a run of any big repo on top of this? Say runtime or ASP?

[epananth]

I noticed that, for non streaming (uploading to symbol server) we get the SymbolExclusion file but dont actually use it. So I added that check too.

I will post the test soon.

[epananth]

Runtime test -> https://dev.azure.com/dnceng/internal/_build/results?buildId=1443339&view=results

[epananth]

Aspnetcore test => https://dev.azure.com/dnceng/internal/_build/results?buildId=1443410&view=results

[epananth]

Reverted the older publishing change, that might break some validation stuff. We do not need this for now. I will create another issue to address that..