Wear Sample uses APIs marked VisibleForTesting

[ataulm]

Raised by Nat here https://b.corp.google.com/u/0/issues/260484640

The APIs have been incorrectly marked as @VisibleForTesting, and a newer release of Play Services should fix this issue.

Since this is only an issue in Electric Eel+, would prefer to wait for the update, rather than suppressing warnings in the sample since we'll have to remove them again anyway when we update.

Opened this issue to point folks towards if they have the same query.