feat: Calculate width/height of canvas based on container dimensions (".excalidraw" selector) & remove props width & height (#3379)

* Remove width/height from the ".excalidraw" container so it will sized automatically.
* updated all ref calculation to ".excalidraw" instead of parent since now ".excalidraw" will get resized
* Remove props width/height as its not needed anymore.
* Resize handler is also not needed anymore.
* Position absolute canvas due to #3379 (comment)

* move css to style and remove one extra rerendering

* factor out mock logic for test

* set height, width so as to avoid unnecessary updates of regression snap

* better mock

* better type checking and omit width,height from getDefaultAppState and also restore

* revert

* default to window dimensions in constructor

* update docs

* update

* update

* tweaks

src/tests/regressionTests.test.tsx

@@ -76,6 +76,7 @@ beforeEach(async () => {
   finger2.reset();
 
   await render(<ExcalidrawApp />);
+  h.setState({ height: 768, width: 1024 });
 });
 
 afterEach(() => {