feat: customize border radius of Views (#42320)

* feat: add View#setBorderRadius

test: initial setBorderRadius tests

fix: robustly set border radius

chore: add PAUSE_CAPTURE_TESTS for easier screencap dev

feat: add view border radius support

test: view border radius

refactor: cleanup view code

* maybe delay capture to fix tests?

* refactor: retry screen captures in an attempt to fix flakiness

* refactor: ScreenCapture constructor no longer async

* increase screen capture timeout, feels a little short

* refactor: move rounded rect util into chromium_src

* skip some capture tests on mas

docs/api/view.md

@@ -94,6 +94,12 @@ Examples of valid `color` values:
 
 **Note:** Hex format with alpha takes `AARRGGBB` or `ARGB`, _not_ `RRGGBBAA` or `RGB`.
 
+#### `view.setBorderRadius(radius)`
+
+* `radius` Integer - Border radius size in pixels.
+
+**Note:** The area cutout of the view's border still captures clicks.
+
 #### `view.setVisible(visible)`
 
 * `visible` boolean - If false, the view will be hidden from display.