Align `FlowManager` APIs across platforms

[sugarmanz]

Is your feature request related to a problem? Please describe.

As a multiplatform construct, the FlowManager API should be consistent across platforms such that consumers can integrate following the same pattern. The current definitions (and key differences) are:

• iOS
  • Default terminate no-op API
  • terminate takes an InProgressState, if there is one
• JVM
  • Base construct generalized, actual FlowManager definition
  • terminate takes no arguments
• React
  • terminate takes a FlowResult['data']

Describe the solution you'd like

At the very least, the same terminate API — for flexibility, it should likely be the InProgressState if there is one (which the FlowResult['data'] can be retrieved from).