Updating the GH_TOKEN for terraform private repo testing to use githu…

…b app installation token. (radius-project#7434)

# Description

Updating the GH_TOKEN for terraform private repo testing to use github
app installation token.

## Type of change

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Fixes: #issue_number

Signed-off-by: Vishwanath Hiremath <vhiremath@microsoft.com>

.github/workflows/functional-test.yaml

@@ -570,7 +570,7 @@ jobs:
           INTEGRATION_TEST_RESOURCE_GROUP_NAME: ${{ env.AZURE_TEST_RESOURCE_GROUP }}
           BICEP_RECIPE_REGISTRY: ${{ env.BICEP_RECIPE_REGISTRY }}
           BICEP_RECIPE_TAG_VERSION: ${{ env.BICEP_RECIPE_TAG_VERSION }}
-          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_TOKEN: ${{ steps.get_installation_token.outputs.token }}
       - uses: azure/setup-kubectl@v4
         if: always()
         with: