Remove UI-test config copy; config now lives in dspace-ui-tests

dspace-ui-tests bundles every customer config and selects it via the NAME
env var, so this workflow no longer checks out this repo or copies the JSON.
Deletes config/config.lindat.ui.tests.json and the two now-unused steps.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Matus Kasak

.github/workflows/playwright-tests.yml

@@ -16,15 +16,6 @@ jobs:
           path: dspace-ui-tests
           token: ${{ secrets.DEPLOY_DEV5_GH_ACTION_DISPATCH }}
 
-      - name: Checkout main repository
-        uses: actions/checkout@v4
-        with:
-          path: this-repository
-
-      - name: Copy customer config to UI tests repository for merging
-        run: |
-          cp this-repository/config/config.lindat.ui.tests.json dspace-ui-tests/customer-constants/
-
       - name: test
         working-directory: dspace-ui-tests/scripts
         env: