feat: pass form save result to onSuccess handler

[Jshhhh]

Problem

Fields object is passed into onSuccess handler in forms. The result of save call would be more helpful

Solution

pass save result to onSuccess handler

Manual tests

Manual save local

Automated tests

• [x] Unit tests added/updated
• [x] E2E tests added/updated
• [ ] N/A - (provide a reason)
• [ ] deferred - (provide GitHub issue for tracking)

Housekeeping

• [x] No non-essential console logs
• [x] All new files contain license notice

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