* Add 'mouseCursor' to TextFormField

Added 'mouseCursor' to TextFormField. 
Related issue: https://github.com/flutter/flutter/issues/99770

* added test for 'mouseCursor' in TextFormField.

added test for 'mouseCursor' in TextFormField.

* Update packages/flutter/test/material/text_form_field_test.dart
Co-authored-by: Tong Mu <dkwingsmt@users.noreply.github.com>

* Update packages/flutter/test/material/text_form_field_test.dart
Co-authored-by: Tong Mu <dkwingsmt@users.noreply.github.com>

* Minor update: Added a space.

* Removed icon & minor updates.
Co-authored-by: Tong Mu <dkwingsmt@users.noreply.github.com>