Added getter errorMessages to reactive_form_field.dart

[MatteMirror]

Added getter errorMessages to reactive_form_field.dart

Connection with Issues

• Close Issue: This pull request addresses and resolves issue Feature Request: Multiple Error Messages Getter #454.

Solution Description

The errorMessages getter has been implemented to retrieve a list of all error messages (in addition to the errorText getter, which only returns the first) associated with the FormControl bound to the widget. Here’s a detailed breakdown of the solution:

• Error Condition: The getter checks if the control has errors and if the _showErrors flag is true.
• If the 'required' error is present, the method returns a list containing the 'required' error message.
• The error message is either a custom validation message (if provided) or the string 'required'.

Handling Other Errors:

• If the 'required' error is not present, the method returns a list of all other error messages.
• For each error key, it looks for a custom validation message.
• If a custom validation message is found, it is used as the error message. Otherwise, the error key itself is used as the error message.
• No Errors or Flag False: If the control has no errors or the _showErrors flag is false, an empty list is returned.

Result

This getter provides more extensive customization options for custom ReactiveTextFields.