fix(cypress): checkout Assistant app repo only on main

Signed-off-by: silver <s.szmajduch@posteo.de>

Author: silverkszlo

.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