[native] introduce loading logic to RelationshipPrompt

Summary:
This diff introduces the loading logic to RelationshipPrompt component

Depends on D12596

Test Plan:
Confirmed that the relationship prompt buttons in the relationship prompt show a loading spinner when the action is in progress

Not loading:

Loading:

Reviewers: inka, ashoat

Reviewed By: ashoat

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D12600