Fix focused expression input outline styling (#9829)

This is necessary due to this change in upstream CodeMirror:

73ec1a70be (diff-0e21fb1c9519a397050defc2148a2d1b966a0982cc4cf196e1e6b007f8d095e5)

Currently the expression input shows a weird dotted outline when focused.

Signed-off-by: Julius Volz <julius.volz@gmail.com>

web/ui/react-app/src/pages/graph/CMTheme.tsx

@@ -2,7 +2,7 @@ import { HighlightStyle, tags } from '@codemirror/highlight';
 import { EditorView } from '@codemirror/view';
 
 export const baseTheme = EditorView.theme({
-  '&': {
+  '&.cm-editor': {
     '&.cm-focused': {
       outline: 'none',
       outline_fallback: 'none',