Handle close modal events with a service.

[danoswaltCL]

TL;DR: This change simplifies logic around handling common modal events. It's a refactor of FF stuff but necessary to not repeat the same funny business with segments. It also provides a "Common Modal Event" service that could be used for other similar situations where building out ngrx infrastructure for temporary values feels like a bit much.

Explanation: We basically have 2 modal close patterns in the newer UI modals:

• Simple Confirm / Delete Modals = we close immediately on submit click, the modal is done whether it is successful or not.
• Complex Form Modals = we want to wait to close only on success, because we want the user to potentially be able to correct an error in the form. This is a little trickier because success is captured in "effects", and we don't necessarily want all of the actions/selectors/reducer/model updates just to store and manage a transient value that is only needed once.

In order to avoid that, we came up with 3 very different and regrettably convoluted patterns to handle http success callbacks and modal event triggers without storing additional state:

• Selectors that look for the addition / removal / or edits to an entity to indirectly infer success.
• Close-modal interceptor configured to close modals when 200 ok returned from certain endpoints.
• Some calls like for import validation are completely bypassing ngrx altogether to be able to handle http calls directly, which is a whole different can-o-worms that I gave up fighting about, now it's just like that.

This change removes the first 2 above in favor of a simple service that can be called from effects. This way seems much more direct and easy to understand. Technically it still violates ngrx patterns because it causes a side-effect that is unmanaged by ngrx, but I think this is fine.

[zackcl]

Do you mean #2320 should go first?

[danoswaltCL]

@zackcl sry i left that comment on wrong PR, this one should go first.