build: update actions

- Updates triggers for UI workflow `lint-frontend`
- Corrects UI paths for `test-invoke-pip` and `test-invoke-pip-skip`

.github/workflows/lint-frontend.yml

@@ -4,9 +4,17 @@ on:
   pull_request:
     paths:
       - 'invokeai/frontend/web/**'
+    types:
+      - 'ready_for_review'
+      - 'opened'
+      - 'synchronize'
   push:
+    branches:
+      - 'main'
     paths:
       - 'invokeai/frontend/web/**'
+  merge_group:
+  workflow_dispatch:
 
 defaults:
   run: