Fix CI: broaden xctestrun search and show raw test output

Remove xcpretty from test-without-building so failures are visible in
CI logs. Broaden .xctestrun glob pattern and add diagnostic output when
the file is not found.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: superhighfives

.github/workflows/tests.yml

@@ -42,11 +42,16 @@ jobs:
       - name: Run tests
         run: |
           set -o pipefail
-          XCTESTRUN=$(find build/DerivedData -name "Pika_*.xctestrun" | head -1)
+          XCTESTRUN=$(find build/DerivedData -name "*.xctestrun" | head -1)
+          echo "Using xctestrun: $XCTESTRUN"
+          if [ -z "$XCTESTRUN" ]; then
+            echo "Error: no .xctestrun file found"
+            find build/DerivedData -type f -name "*.xctestrun" || true
+            exit 1
+          fi
           xcodebuild test-without-building \
             -xctestrun "$XCTESTRUN" \
-            -destination 'platform=macOS' \
-            2>&1 | xcpretty --color
+            -destination 'platform=macOS'
 
       - name: Upload test results
         if: always()