UI test shenanigans (#2611)

* Hardcode Xcode 15.2 as there are multiple versions available on the performance runner

* Remove the derived data caching step as it's not necessary on the performance runner.

.github/workflows/ui_tests.yml

@@ -23,11 +23,6 @@ jobs:
     steps:
       - uses: nschloe/action-cached-lfs-checkout@v1
 
-      - uses: irgaly/xcode-cache@v1
-        with:
-          key: xcode-cache-deriveddata-${{ github.workflow }}-${{ github.ref }}
-          restore-keys: xcode-cache-deriveddata-${{ github.workflow }}-${{ github.ref }}
-
       - uses: actions/cache@v3
         with:
           path: vendor/bundle