Use Unofficial 1ES templates for pull_request.yml (#5718)

Author: donnie-msft

eng/pipelines/pull_request.yml

@@ -54,7 +54,7 @@ variables:
   RunTestsOnMac: ${{ parameters.RunTestsOnMac }}
   RunMonoTestsOnMac: ${{ parameters.RunMonoTestsOnMac }}
 extends:
-  template: azure-pipelines/MicroBuild.1ES.Official.yml@MicroBuildTemplate
+  template: azure-pipelines/MicroBuild.1ES.Unofficial.yml@MicroBuildTemplate
   parameters:
     sdl:
       sourceAnalysisPool: VSEngSS-MicroBuild2022-1ES