[Build]reintroduce variables.EnablePipelineCache (#35087)

* build: reintroduce variables.EnablePipelineCache

.pipelines/v2/ci.yml

@@ -32,7 +32,7 @@ parameters:
   - name: enableMsBuildCaching
     type: boolean
     displayName: "Enable MSBuild Caching"
-    default: false
+    default: true
   - name: runTests
     type: boolean
     displayName: "Run Tests"

.pipelines/v2/templates/pipeline-ci-build.yml

@@ -3,6 +3,9 @@ variables:
     value: false
   - name: EnablePipelineCache
     value: true
+  - ${{ if eq(parameters.enableMsBuildCaching, true) }}:
+    - name: EnablePipelineCache
+      value: true
 
 parameters:
   - name: buildPlatforms