fix: set edit context to undefined in dispose (microsoft#256965)

Author: SimonSiefke

src/vs/editor/browser/controller/editContext/native/nativeEditContext.ts

@@ -210,6 +210,7 @@ export class NativeEditContext extends AbstractEditContext {
 
 	public override dispose(): void {
 		// Force blue the dom node so can write in pane with no native edit context after disposal
+		this.domNode.domNode.editContext = undefined;
 		this.domNode.domNode.blur();
 		this.domNode.domNode.remove();
 		this._imeTextArea.domNode.remove();