Improve design of the rich text editor (#9533)

New design for rich text composer

test/setup/setupManualMocks.ts

@@ -31,6 +31,29 @@ class ResizeObserver {
 }
 window.ResizeObserver = ResizeObserver;
 
+// Stub DOMRect
+class DOMRect {
+    x = 0;
+    y = 0;
+    top = 0;
+    bottom = 0;
+    left = 0;
+    right = 0;
+    height = 0;
+    width = 0;
+
+    static fromRect() {
+        return new DOMRect();
+    }
+    toJSON() {}
+}
+
+window.DOMRect = DOMRect;
+
+// Work around missing ClipboardEvent type
+class MyClipboardEvent {}
+window.ClipboardEvent = MyClipboardEvent as any;
+
 // matchMedia is not included in jsdom
 const mockMatchMedia = jest.fn().mockImplementation(query => ({
     matches: false,
@@ -51,6 +74,7 @@ global.URL.revokeObjectURL = jest.fn();
 // polyfilling TextEncoder as it is not available on JSDOM
 // view https://github.com/facebook/jest/issues/9983
 global.TextEncoder = TextEncoder;
+// @ts-ignore
 global.TextDecoder = TextDecoder;
 
 // prevent errors whenever a component tries to manually scroll.
@@ -60,4 +84,5 @@ window.HTMLElement.prototype.scrollIntoView = jest.fn();
 fetchMock.config.overwriteRoutes = false;
 fetchMock.catch("");
 fetchMock.get("/image-file-stub", "image file stub");
+// @ts-ignore
 window.fetch = fetchMock.sandbox();