Replacing react-sortable-hoc with dnd-kit (#1359)

## Launch Checklist

This PR replace react-sortable-hoc which is unmaintained with dnd-kit

- Resolves #1016
- Replaces the following PR: #1259

I've tested it locally to make sure it does what it should.
I'll see if I can add a test...

 - [x] Briefly describe the changes in this PR.
 - [x] Link to related issues.
 - [x] Write tests for all new functionality.
 - [x] Add an entry to `CHANGELOG.md` under the `## main` section.

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

src/components/ModalAdd.tsx

@@ -175,7 +175,6 @@ class ModalAddInternal extends React.Component<ModalAddInternalProps, ModalAddSt
         }
         {!NON_SOURCE_LAYERS.includes(this.state.type) &&
       <FieldSourceLayer
-        isFixed={true}
         sourceLayerIds={layers}
         value={this.state['source-layer']}
         onChange={(v: string) => this.setState({ 'source-layer': v })}