[ios, macos] Added missing mapViewDidBecomeIdle for iOS. Fixed typo.

[julianrex]

Follow on from #13513

This PR adds the mapViewDidBecomeIdle method to iOS, and fixes the selector check in the macOS version.

[ChrisLoer]

😳 Thanks for the fixups!

[julianrex]

@ChrisLoer I noticed that this seems to fire at the start of a camera transition - is that expected behavior? I wonder if we need a paired method, something like mapViewDidEndIdle

[ChrisLoer]

I noticed that this seems to fire at the start of a camera transition

Do you mean a programmatically started transition or one with a touch interaction? I saw the "fire at the beginning" behavior when doing a touch pan on an iOS device, and looking in the debugger I came to the conclusion is that what happened is the first touch caused a frame to render before any motion/animation had registered, so that first frame fired the "idle" event (technically true).

[julianrex]

I came to the conclusion is that what happened is the first touch caused a frame to render before any motion/animation had registered, so that first frame fired the "idle" event (technically true).

Yep that matches what I was seeing.