Improve camera.fly animation smoothness or add an animation curve parameter

New Feature

Refine the camera.fly method for smoother transitions. The current iOS implementation feels abrupt in comparison to the JS version of Mapbox, which provides a smoother experience by quickly starting and slowly easing into the destination. I would suggest adding an optional animation curve parameter like camera.ease, or by default, refining the existing animation to more closely mirror the JS version.

Solution Suggestions:

1. Add an animation curve parameter in the camera.fly method.
2. Modify the default animation to align with the JS version's smoothness.

Why

A smoother transition enhances user experience by reducing visual jarring and ensures consistent behavior across platforms.

Note:
Updates on issue #990 would be appreciated, which also affects the smoothness of the animation.

Start by tracing the iOS implementation of camera.fly and compare its transition behavior with the JavaScript Mapbox version; also review issue #990 for related context. Done means the fly transition is measurably smoother and either supports an optional animation curve like camera.ease or matches the proposed default behavior.