Re-enable IBC by default (#48546)

Author: mmitche

Diff for: eng/pipelines/templates/variables/vmr-build.yml

@@ -44,10 +44,9 @@ variables:
     value: false
 - ${{ elseif or(startsWith(parameters.desiredIBC, 'Default'), eq(parameters.desiredIBC, '')) }}:
   # Enable IBC on the internal project if the, branch is a main or release branch
-  - ${{ if and(eq(variables['System.TeamProject'], 'internal'), or(eq(variables['Build.SourceBranch'], 'refs/heads/main'), startsWith(variables['Build.SourceBranch'], 'refs/heads/internal/release/'), and(startsWith(variables['Build.SourceBranch'], 'refs/heads/release/'), contains(variables['Build.SourceBranch'], '-preview')))) }}:
-    # IBC disabled until Mismatched MVIDs issue resolved. https://github.com/dotnet/source-build/issues/4954
+  - ${{ if and(eq(variables['System.TeamProject'], 'internal'), or(eq(variables['Build.SourceBranch'], 'refs/heads/main'), startsWith(variables['Build.SourceBranch'], 'refs/heads/internal/release/'), startsWith(variables['Build.SourceBranch'], 'refs/heads/release/'))) }}:
     - name: ibcEnabled
-      value: false
+      value: true
   # No IBC otherwise.
   - ${{ else }}:
     - name: ibcEnabled