Start using the `sdk [SHA]` tag in the release pipeline

[premun]

Once we switch the main of the VMR to be synchronized from dotnet/sdk, the tag on the VMR pipelines will change from install [SHA] to sdk [SHA].
We use this tag to find the associated pipeline runs. We will need to make 9.0 release look for this tag.

[ellahathaway]

Related to #4357. Draft PR with changes: https://dev.azure.com/dnceng/internal/_git/dotnet-release/pullrequest/39308 (internal Microsoft link). Planning on updating/publishing the PR once we switch the VMR to sync from dotnet/sdk.

[ellahathaway]

Update: Waiting to update the draft PR until the Staging pipeline is releasing from SDK.

[ellahathaway]

Closing since the PR was merged https://dev.azure.com/dnceng/internal/_git/dotnet-release/pullrequest/39308