Update UI test workflow for self-hosted runners

Changed concurrency group to a static name for self-hosted runners and removed simulator setup steps, streamlining the workflow for macOS self-hosted environments.

Author: gemcoder21

.github/workflows/ui_tests.yml

@@ -20,8 +20,10 @@ jobs:
     steps:
       - name: Setup simulator for runner
         run: |
-          echo "SIMULATOR_NAME=${{ runner.name }}-iPhone" >> $GITHUB_ENV
-          xcrun simctl create "${{ runner.name }}-iPhone" "iPhone 17" 2>/dev/null || true
+          SIMULATOR_NAME="${{ runner.name }}-iPhone"
+          echo "SIMULATOR_NAME=$SIMULATOR_NAME" >> $GITHUB_ENV
+          xcrun simctl delete "$SIMULATOR_NAME" 2>/dev/null || true
+          xcrun simctl create "$SIMULATOR_NAME" "iPhone 17"
 
       - name: Setup sccache for GitHub-hosted
         if: runner.environment == 'github-hosted'