Codemirror 5 to 6 upgrade (#1386)

## Launch Checklist

- Resolves #891

This PR upgrades code mirror from version 5 to version 6.
It should not change any functionality dramatically.
The filter and other expressions have line numbers now as I was not able
to remove those without introducing a lot of code, which I preferred not
to.

Before:

<img width="571" height="933" alt="image"
src="https://github.com/user-attachments/assets/02f047ee-0857-4eb1-9431-2620099ea025"
/>


After:
<img width="571" height="933" alt="image"
src="https://github.com/user-attachments/assets/7cf60155-7cd9-4c06-915e-dec2ae8247fc"
/>



 - [x] Briefly describe the changes in this PR.
 - [x] Link to related issues.
- [x] Include before/after visuals or gifs if this PR includes visual
changes.
 - [x] Write tests for all new functionality.
 - [x] Add an entry to `CHANGELOG.md` under the `## main` section.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

cypress/e2e/maputnik-driver.ts

@@ -195,6 +195,10 @@ export class MaputnikDriver {
 
     collapseGroupInLayerEditor: (index = 0) => {
       this.helper.get.element(".maputnik-layer-editor-group__button").eq(index).realClick();
+    },
+
+    appendTextInJsonEditor: (text: string) => {
+      this.helper.get.element(".cm-line").first().click().type(text, { parseSpecialCharSequences: false });
     }
   };