feat: add pull request trigger for firewall escape test workflow

Signed-off-by: Jiaxiao (mossaka) Zhou <duibao55328@gmail.com>

Author: Mossaka

.github/workflows/test-firewall-escape.lock.yml

@@ -6,6 +6,9 @@ on:
   workflow_dispatch:
   push:
     branches: [main]
+  pull_request:
+    types: [labeled]
+    names: ['firewall-escape-test']
 
 permissions:
   contents: read