Skip Lambda integration tests for fork PRs (#14257)

.circleci/config.yml

@@ -109,7 +109,9 @@ commands:
         type: env_var_name
         default: ROLE_ARN
     steps:
+      # Only run the assume-role command for the main repo. The AWS credentials aren't available for forks.
       - run: |
+          if [[ "${CIRCLE_BRANCH%%/*}/" != "pull/" ]]; then
             export AWS_ACCESS_KEY_ID="${<< parameters.access-key >>}"
             export AWS_SECRET_ACCESS_KEY="${<< parameters.secret-key >>}"
             export ROLE_ARN="${<< parameters.role-arn >>}"
@@ -118,6 +120,7 @@ commands:
             echo "export AWS_ACCESS_KEY_ID=$(echo $CREDENTIALS | jq -r '.AccessKeyId')" >> $BASH_ENV
             echo "export AWS_SECRET_ACCESS_KEY=$(echo $CREDENTIALS | jq -r '.SecretAccessKey')" >> $BASH_ENV
             echo "export AWS_SESSION_TOKEN=$(echo $CREDENTIALS | jq -r '.SessionToken')" >> $BASH_ENV
+          fi
 
   run-go-test-full:
     parameters: