TextEditor: setState should not be invoked if the state didn't change
TextEditor: setState should not be invoked if the state didn't change

Using the text editor in lit-html templates like this

```
<devtools-text-editor .state=${this.#editorState}>
</devtools-text-editor>
```

might result in broken scrolling if the parent component needs
to re-render based on scroll position resulting in the calls
to activeEditor.setState to happen during scrolling.

Bug: none
Change-Id: Icd4b4d820322377cf6b2009fc84a8bdecda02bd6
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/4028939
Commit-Queue: Alex Rudenko <d8d88e7d7e77f69e23d1d1432231196fb8e02a62@chromium.org>
Reviewed-by: Benedikt Meurer <024a1e0af501338d11c3b837c6193d11c140d792@chromium.org>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend