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>

src/libs/layer.ts

@@ -1,7 +1,8 @@
 import {latest} from "@maplibre/maplibre-gl-style-spec";
 import { type LayerSpecification } from "maplibre-gl";
 
-export function changeType(layer: LayerSpecification, newType: string) {
+
+export function changeType(layer: LayerSpecification, newType: string): LayerSpecification {
   const changedPaintProps: LayerSpecification["paint"] = { ...layer.paint };
   Object.keys(changedPaintProps).forEach(propertyName => {
     if(!(propertyName in latest["paint_" + newType])) {
@@ -20,8 +21,8 @@ export function changeType(layer: LayerSpecification, newType: string) {
     ...layer,
     paint: changedPaintProps,
     layout: changedLayoutProps,
-    type: newType,
-  };
+    type: newType
+  } as LayerSpecification;
 }
 
 /** A {@property} in either the paint our layout {@group} has changed