Indicate different submitting states on <ModalAddReport>

[ewen-lbh]

Is your feature request related to a problem? Please describe.
The bug report/feature request modal does not actually make a request to the API, and it is not clear whether the report is currently submitting or is already submitted

Describe the solution you'd like
Add two states to the modal (with <ScreenSTATE> components), one for a report currently submitting, one for a report that is submitted:

• submitting state: a spinner with a "submitting" text below it
• submitted state: a thumbs-up image and a button to go to the reports (already sort-of implemented)