Fix failing tests (#327)

* try to fix failing tests

* continue on error

* remove Flutter versions that aren't available natively for arm64 macOS

* explicitly specify arch = x64 (`-a x64`)

* fix order of args

* remove redundant quotes

* make `dry-run` also accept bools

action.yaml

@@ -112,7 +112,7 @@ runs:
 
     - name: Run setup script
       shell: bash
-      if: ${{ inputs.dry-run != 'true' }}
+      if: ${{ inputs.dry-run != 'true' && inputs.dry-run != true }}
       run: |
         $GITHUB_ACTION_PATH/setup.sh \
           -n '${{ steps.flutter-action.outputs.VERSION }}' \