[native] Update native to match new landing SIWE behavior

Summary:
I separated this out into its own commit to make it easier to test the old native with the new landing. I wanted to make sure we didn't break old clients.

1. Resize BottomSheet to specific values when the WalletConnect modal is open.
2. Style the handle to match the WebView when the WalletConnect modal is open.

Depends on D8253

Test Plan:
Tested with the rest of the stack. I tested all three SIWE endpoints:

1. Web
2. Native (old flow)
3. Native (new flow)

For each, I tested both Rainbow and WalletConnect (both of which need WalletConnect), and navigated around the WalletConnect modal to various places.

I also tested both the new native client (as of this diff) as well as the old one (as of the previous diff). The new client resizes better, but the old client is still usable.

Reviewers: atul, ginsu

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8254