fix: Prevent unnecessary content changes clearing redo actions

In this context, `this.value` is not a string but a instance of
`RichTextData`. Therefore, comparing the two values results in
unexpected inequality, triggering an update of the block's
`attributes.content` toggling it from a `ReactTextData` instance to a
string. This toggle results in the undo manager tracking the change as
a new line of editor history, clearing out any pending redo actions.

The `RichTextData` type was introduced in #43204. Invoking `toString`
may not be the best long-term solution to this problem. Refactoring the
rich text implementation to appropriately leverage `RichTextData` and
(potentially) treat `value` and `record` values different and storing
them separately may be necessary.

packages/block-editor/src/components/rich-text/native/index.native.js

@@ -336,7 +336,7 @@ export class RichText extends Component {
 		);
 
 		this.debounceCreateUndoLevel();
-		const refresh = this.value !== contentWithoutRootTag;
+		const refresh = this.value.toString() !== contentWithoutRootTag;
 		this.value = contentWithoutRootTag;
 
 		// We don't want to refresh if our goal is just to create a record.