Try to fix the CI (#232)

Author: krassowski

ui-tests/inject-test-config.sh

@@ -1,5 +1,5 @@
 set -eux
 # Overwrite some settings to disable cursor blinking,
 # which causes inadvertent playwright snapshot failures
-cat jupyter-lite.json | jq '.["jupyter-config-data"].["settingsOverrides"] += {"@jupyterlab/codemirror-extension:plugin":{ "defaultConfig": { "cursorBlinkRate": 0 } } }' > jupyter-lite.json.tmp
+cat jupyter-lite.json | jq '.["jupyter-config-data"].["settingsOverrides"] += {"@jupyterlab/codemirror-extension:plugin":{ "defaultConfig": { "cursorBlinkRate": 0, "lineNumbers": false } } }' > jupyter-lite.json.tmp
 mv jupyter-lite.json.tmp jupyter-lite.json