Remove runtime patch that disabled package validation

[lbussell]

Part of dotnet/source-build#2708

We initially created this patch for runtime's release/6.0 branch to work around some reliability issues with package validation: dotnet/runtime#60881

I ported this patch to main but apparently the reliability issues were fixed a while ago: dotnet/runtime#63601 (comment). As a result, this patch isn't necessary anymore.

[MichaelSimons]

@lbussell - Can you link to the runtime PR that address the stability issues? What branch were these made in? I am wondering if they were backported to 6.0.

[lbussell]

Here is where the patch was merged into release/6.0.

Here is the issue we were using to track backporting the flaky build fixes that can probably be closed now (edit: it should not be closed, the changes have not been backported to 6.0). It links to two PRs (dotnet/runtime#60847, dotnet/sdk#22277) that have been merged that seem to address the issue.

[safern]

I am wondering if they were backported to 6.0.

We haven't backported them to 6.0. I will work on that for the 6.0.3 release. I'll let you know so that you can remove the patch on 6.0.