fix(action): correct quoting in workflow expressions (#293)

Corrects the quoting of GitHub Actions expressions in `action.yml`. The
expression parser was failing when an expression contained single quotes
while also being wrapped in single quotes.

This change switches to using double quotes to wrap expressions that
contain single quotes, which resolves the parsing error and ensures the
workflow functions correctly.

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Signed-off-by: Jerop Kipruto <jerop@google.com>

Author: jerop

action.yml

@@ -84,11 +84,11 @@ runs:
       shell: 'bash'
       run: '${{ github.action_path }}/scripts/validate-inputs.sh'
       env:
-        INPUT_GEMINI_API_KEY_PRESENT: '${{ inputs.gemini_api_key != '' }}'
-        INPUT_GOOGLE_API_KEY_PRESENT: '${{ inputs.google_api_key != '' }}'
-        INPUT_GCP_WORKLOAD_IDENTITY_PROVIDER_PRESENT: '${{ inputs.gcp_workload_identity_provider != '' }}'
-        INPUT_GCP_PROJECT_ID_PRESENT: '${{ inputs.gcp_project_id != '' }}'
-        INPUT_GCP_SERVICE_ACCOUNT_PRESENT: '${{ inputs.gcp_service_account != '' }}'
+        INPUT_GEMINI_API_KEY_PRESENT: "${{ inputs.gemini_api_key != '' }}"
+        INPUT_GOOGLE_API_KEY_PRESENT: "${{ inputs.google_api_key != '' }}"
+        INPUT_GCP_WORKLOAD_IDENTITY_PROVIDER_PRESENT: "${{ inputs.gcp_workload_identity_provider != '' }}"
+        INPUT_GCP_PROJECT_ID_PRESENT: "${{ inputs.gcp_project_id != '' }}"
+        INPUT_GCP_SERVICE_ACCOUNT_PRESENT: "${{ inputs.gcp_service_account != '' }}"
         INPUT_USE_VERTEX_AI: '${{ inputs.use_vertex_ai }}'
         INPUT_USE_GEMINI_CODE_ASSIST: '${{ inputs.use_gemini_code_assist }}'
     - name: 'Configure Gemini CLI'