fix: #1474 improve form state updates

[deandreamatias]

Connection with issue(s)

Close #1474

Solution description

Screenshots or Videos

To Do

• Read contributing guide
• Check the original issue to confirm it is fully satisfied
• Add solution description to help guide reviewers
• Add unit test to verify new or fixed behaviour
• If apply, add documentation to code properties and package readme

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.61%. Comparing base (fffb27d) to head (6421658).
⚠️ Report is 56 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/src/form_builder.dart	66.66%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1487      +/-   ##
==========================================
- Coverage   89.88%   89.61%   -0.28%     
==========================================
  Files          21       21              
  Lines         840      847       +7     
==========================================
+ Hits          755      759       +4     
- Misses         85       88       +3     

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