[Android] Revert arm and arm64 device PR runs (#53210)

We're still having capacity issues even after doubling the number of devices.  Only run device tests on the rolling build for the time being.

Co-authored-by: Steve Pfister <[email protected]>

Author: steveisok

eng/pipelines/runtime-staging.yml

@@ -162,16 +162,19 @@ jobs:
           eq(dependencies.evaluate_paths.outputs['SetPathVars_mono.containsChange'], true),
           eq(dependencies.evaluate_paths.outputs['SetPathVars_installer.containsChange'], true),
           eq(variables['isFullMatrix'], true))
-      # extra steps, run tests
-      extraStepsTemplate: /eng/pipelines/libraries/helix.yml
-      extraStepsParameters:
-        creator: dotnet-bot
-        testRunNamePrefixSuffix: Mono_$(_BuildConfig)
-        condition: >-
-          or(
-          eq(variables['librariesContainsChange'], true),
-          eq(variables['monoContainsChange'], true),
-          eq(variables['isFullMatrix'], true))
+      
+      # don't run tests on PRs until we can get significantly more devices
+      ${{ if eq(variables['isFullMatrix'], true) }}:
+        # extra steps, run tests
+        extraStepsTemplate: /eng/pipelines/libraries/helix.yml
+        extraStepsParameters:
+          creator: dotnet-bot
+          testRunNamePrefixSuffix: Mono_$(_BuildConfig)
+          condition: >-
+            or(
+            eq(variables['librariesContainsChange'], true),
+            eq(variables['monoContainsChange'], true),
+            eq(variables['isFullMatrix'], true))
 
 #
 # Build the whole product using Mono and run libraries tests