[PETOSS-829] Increase timeout

Runs pretty commonly take around 5 minutes, so leaving a couple of minutes spare

Author: the-chris-mitchell

.github/workflows/pr-codegen-validation.yml

@@ -83,4 +83,5 @@ jobs:
                 repo: xeroapi-sdk-codegen
                 owner: xero-internal
                 run_id: ${{ steps.codegen_workflow.outputs.run_id }}
+                run_timeout_seconds: 420 # 7 minutes