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/styles/_codemirror.scss

@@ -1,100 +0,0 @@
-@use "vars";
-
-.CodeMirror-lint-tooltip {
-  z-index: 2000 !important;
-}
-
-.codemirror-container {
-  max-width: 100%;
-  position: relative;
-  overflow: auto;
-}
-
-.cm-s-maputnik.CodeMirror {
-  height: 100%;
-  font-size: 12px;
-  background: transparent;
-}
-
-.cm-s-maputnik.CodeMirror, .cm-s-maputnik .CodeMirror-gutters {
-  color: #8e8e8e;
-  border: none;
-}
-
-.cm-s-maputnik .CodeMirror-gutters {
-  background: #212328;
-}
-
-.cm-s-maputnik .CodeMirror-cursor {
-    border-left: solid thin #f0f0f0 !important;
-}
-
-.cm-s-maputnik.CodeMirror-focused div.CodeMirror-selected {
-  background: rgba(255, 255, 255, 0.10);
-}
-
-.cm-s-maputnik .CodeMirror-line::selection,
-.cm-s-maputnik .CodeMirror-line > span::selection,
-.cm-s-maputnik .CodeMirror-line > span > span::selection {
-  background: rgba(255, 255, 255, 0.10);
-}
-
-.cm-s-maputnik .CodeMirror-line::-moz-selection,
-.cm-s-maputnik .CodeMirror-line > span::-moz-selection,
-.cm-s-maputnik .CodeMirror-line > span > span::-moz-selection {
-  background: rgba(255, 255, 255, 0.10);
-}
-
-.cm-s-maputnik span.cm-string, .cm-s-maputnik span.cm-string-2 {
-  color: #8f9d6a;
-}
-.cm-s-maputnik span.cm-number { color: #91675f; }
-.cm-s-maputnik span.cm-property { color: #b8a077; }
-
-.cm-s-maputnik .CodeMirror-activeline-background {
-  background: rgba(255,255,255,0.1);
-}
-
-.cm-s-maputnik .CodeMirror-matchingbracket {
-  background: hsla(223, 12%, 35%, 1);
-  color: vars.$color-white !important;
-}
-
-.cm-s-maputnik .CodeMirror-nonmatchingbracket {
-  background-color: #bb0000;
-  color: white !important;
-}
-
-@keyframes JSONEditor__animation-fade {
-  from {
-    opacity: 1;
-  }
-  to {
-    opacity: 0;
-  }
-}
-
-.JSONEditor__message {
-  position: absolute;
-  right: 0;
-  font-size: 0.85em;
-  z-index: 99999;
-  padding: 0.3em 0.5em;
-  background: hsla(0, 0%, 0%, 0.3);
-  color: vars.$color-lowgray;
-  border-bottom-left-radius: 2px;
-  transition: opacity 320ms ease;
-  opacity: 0;
-  pointer-events: none;
-
-  &--on {
-    opacity: 1;
-    animation: 320ms ease 0s JSONEditor__animation-fade;
-    animation-delay: 2000ms;
-    animation-fill-mode: forwards;
-  }
-
-  kbd {
-    font-family: monospace;
-  }
-}

src/styles/index.scss

@@ -15,7 +15,6 @@
 @use 'zoomproperty';
 @use 'popup';
 @use 'map';
-@use 'codemirror';
 @use 'react-collapse';
 
 .maputnik-layout {