Update CI trigger rules (#712)

Author: aliberts

.github/workflows/quality.yml

@@ -4,8 +4,6 @@ on:
   workflow_dispatch:
   workflow_call:
   pull_request:
-    branches:
-      - main
   push:
     branches:
       - main

.github/workflows/test-docker-build.yml

@@ -4,8 +4,6 @@ name: Test Dockerfiles
 
 on:
   pull_request:
-    branches:
-      - main
     paths:
       # Run only when DockerFile files are modified
       - "docker/**"

.github/workflows/test.yml

@@ -2,8 +2,6 @@ name: Tests
 
 on:
   pull_request:
-    branches:
-      - main
     paths:
       - "lerobot/**"
       - "tests/**"