Fix branch filters for the VMR synchronization (#15161)

eng/pipelines/templates/jobs/vmr-synchronization.yml

@@ -64,4 +64,4 @@ jobs:
         git push dotnet ${{ parameters.vmrBranch }}
       displayName: Push changes to dotnet/dotnet
       workingDirectory: $(vmrPath)
-      condition: and(succeeded(), or(eq('${{ parameters.vmrBranch }}', 'main'), startsWith('${{ parameters.vmrBranch }}', 'release/')))
+      condition: and(succeeded(), or(eq(variables['vmrBranch'], 'main'), startsWith(variables['vmrBranch'], 'release/')))

eng/pipelines/templates/steps/vmr-pull-updates.yml

@@ -29,7 +29,9 @@ steps:
   displayName: Restore darc
   workingDirectory: $(Agent.BuildDirectory)/installer
 
-- script: git checkout -B ${{ parameters.vmrBranch }}
+- script: |
+    git checkout -B ${{ parameters.vmrBranch }}
+    echo "##vso[task.setvariable variable=vmrBranch]${{ parameters.vmrBranch }}"
   displayName: Prepare branch ${{ parameters.vmrBranch }}
   workingDirectory: ${{ parameters.vmrPath }}