Summary: This diff fixes the flow errors that surfaced from flow-typing DialogManagerAndorid and deleting NativeDialogManagerAndroid. I also migrated all imports of NativeDialogManagerAndorid to import the module from `react-native-implementation.js`.
Reviewed By: fkgozali
Differential Revision: D15440162
fbshipit-source-id: 2fdfb68104bc8ffb93c0c77fe15aacadc182f62f