Disable iOS arm PR builds (#34467)

* Disable iOS arm PR builds

Infrastructure issue: #34465

* Add tracking issue and disable installer iOS arm build too

Author: akoeplinger

eng/pipelines/runtime.yml

@@ -378,7 +378,7 @@ jobs:
     buildConfig: Release
     runtimeFlavor: mono
     platforms:
-    - iOS_arm
+    # - iOS_arm # https://github.com/dotnet/runtime/issues/34465
     - iOS_arm64
     - iOS_x64
     jobParameters:
@@ -390,7 +390,7 @@ jobs:
     buildConfig: Debug
     runtimeFlavor: mono
     platforms:
-    - iOS_arm
+    # - iOS_arm # https://github.com/dotnet/runtime/issues/34465
     - iOS_arm64
     - iOS_x64
     jobParameters: