fix(app): wait for maintenance run deletion before closing flows

[smb2268]

fix RABR-290

Overview

In two previous PR's we stopped waiting for a maintenance run to get deleted before closing gripper and wizard flows. This fixed a few visual bugs where the spinner was removed before the modals closed, but caused a bug where you could try to create a new maintenance run before the previous one was deleted. This PR adds back in waiting for the delete mutation to resolve before exiting and adds logic to show the spinner while the mutation is loading.

Test Plan

1. Ensure this fixes the bug where opening, quickly closing, and opening another gripper flow causes a 500 error since the deletion isn't complete before another is created
2. Exit out of pipette and gripper flows and ensure the loader shows from the time the home begins to the time the modal is closed

Changelog

1. Move closeFlow() back to the resolve call back of useDeleteMaintenanceRunMutation
2. Grab isLoading from the same mutation and use it wherever we show a spinner

Review requests

Quick code check - @ncdiehl11, @vegano1 and I have done some testing on this

Risk assessment

Low

[ncdiehl11]

tested and code looks good to me. thanks!