Merge pull request #8124 from nextcloud/backport/8116/stable31

[stable31] fix(ci): Only build Assistant from git for main branch

Author: max-nextcloud

.github/workflows/cypress-e2e.yml

@@ -46,6 +46,7 @@ jobs:
           path: apps/viewer
 
       - name: Checkout assistant
+        if: matrix.server-versions == 'main'
         uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
         with:
           persist-credentials: false
@@ -83,6 +84,7 @@ jobs:
           TESTING=true npm run build --if-present
 
       - name: Install node dependencies & build assistant app
+        if: matrix.server-versions == 'main'
         working-directory: apps/assistant
         run: |
           composer install --no-dev