[native] Pass on nativeSetUserAvatar's Promise to actionSheetConfig

Summary:
actionSheetConfig can take a => mixed function here, so we can pass the Promise directly to avoid triggering unused-promise Flow lint.

Dependds on D10166

Test Plan: Flow

Reviewers: atul, ginsu

Reviewed By: ginsu

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D10167