Fix iOS Initializing speed

[BradleyAlcock]

Added UpdateCameraStart to move the point where captureSession.StartRunning() first fires to the last option that causes UpdateCamera to fire, MapVisibility. This reduces initialization time by a few seconds
fixes #319

[jfversluis]

@BradleyAlcock Could you test #321 as a safe alternative? It keeps startup in Connect; a MapVisibility-owned start can be skipped by CameraView, custom mappers, or lifecycle ordering.

[BradleyAlcock]

@jfversluis #321 tested across 3 scenarios, plain big island, moving to a different page and setting a property . All worked well, much more elegant solution, thank you.

[jfversluis]

Closing in favor of #321, which preserves connection-owned startup while avoiding redundant AVFoundation reconfiguration and stop/start cycles. Thanks @BradleyAlcock for identifying and profiling the issue.