refactor(ProcessEditor): Decouple integration with BFF when adding tasks in the process editor.

[framitdavid]

Description

Continuing cleaning up the process editor to make it more independent of domain knowledge when adding events. When tasks such as payment are added, the app development controls which API calls and side effects should be carried out.

We still need to refine the handling of custom receipts, which will likely need to be changed in a separate PR. But after that, I think we can avoid passing React Query methods down to the process-editor package, which means that we might delete the BpmnApiContext afterwards!

Added skip-releasenotes on this one, since its refactoring only.

Related Issue(s)

• PR itself

Verification

• [x] Your code builds clean without any errors or warnings
• [x] Manual testing done (required)
• [x] Relevant automated test added (if you find this hard, leave it and we'll help out)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.06%. Comparing base (6258b3b) to head (62b87af). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #12894 +/- ## ========================================== - Coverage 91.07% 91.06% -0.01% ========================================== Files 1396 1393 -3 Lines 19751 19732 -19 Branches 2391 2389 -2 ========================================== - Hits 17988 17969 -19 Misses 1501 1501 Partials 262 262 ```

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[framitdavid]

A lot of great code! 😄 Added some comments

Thanks! I have answered some of your comments and fixed some! Assigning the review back to you. :)