Cannot run test-signed `official.yml` pipeline

[MiYanni]

As part of the OptProf changes, I changed the signing of our assemblies/packages. Tom asked if we could have a test signing option, since this was removed as part of our build pipeline and moved to our CI pipeline. I added this as a runtime parameter for our pipeline, since it is just one value that gets set between real and test.

However, I didn't check to see if setting it to test actually worked. There seems to be an issue with how we end up signing our assemblies where it isn't smart enough to recognize that certain assemblies are already signed. At this time, I'm not exactly sure the circumstances why we already have a fully-signed assembly, but this causes the pipeline to fail.

This is confusing because it says that it was successfully signed, but then has an error. Then, it repeats trying to run the strong name utility on it, failing over and over again on a retry loop. This would need to be investigated and fixed if we need test-signed builds.

[MiYanni]

As of #8420, the test sign parameter is no longer present because of this issue. When investigating, the parameter needs to be added back to the official.yml.

[drewnoakes]

@phenning got this working.