Add warning and update PR checks for Swift on Linux (#2399)

* PR checks: Only run Swift build command on MacOS
* PR checks: update to only test Swift on MacOS
* Log warning if workflow is running Swift on Ubuntu
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Co-authored-by: Andrew Eisenberg <aeisenberg@github.com>

.github/workflows/debug-artifacts.yml

@@ -52,9 +52,8 @@ jobs:
           debug: true
           debug-artifact-name: my-debug-artifacts
           debug-database-name: my-db
-      - uses: ./../action/.github/actions/setup-swift
-        with:
-          codeql-path: ${{ steps.init.outputs.codeql-path }}
+          # We manually exclude Swift from the languages list here, as it is not supported on Ubuntu
+          languages: cpp,csharp,go,java,javascript,python,ruby 
       - name: Build code
         shell: bash
         run: ./build.sh