Prevent `$(AndroidUseLatestPlatformSdk)` from using Unstable APIs

[dellis1972]

Currently if a user sets $(AndroidUseLatestPlatformSdk) the system will pickup the very latest binding target framework, regardless of if it is stable or not.

What we should be doing is using the latest Stable API rather than just grabbing the max.
That said we still want the user to be able to use the unstable API if they really want to. So regardless of $(AndroidUseLatestPlatformSdk) is set to true, if the user has set the $(TargetFrameworkVersion) to the value of an unstable API we should allow the user to use it.

So the new logic is as follows

1. $(AndroidUseLatestPlatformSdk) = true, use the latest stable API
2. $(TargetFrameworkVersion) = and unstable version and $(AndroidUseLatestPlatformSdk) = false, use the $(TargetFrameworkVersion).
   3.$(TargetFrameworkVersion) = and unstable version and $(AndroidUseLatestPlatformSdk) = true, use the $(TargetFrameworkVersion)