improve and fix Replicate Form action

[atmonshi]

No description provided.

[what-the-diff]

PR Summary

• Added a safety check in 'FieldsContract.php'
  An extra condition was implemented in src/Fields/FieldsContract.php to ensure the dataSource class already exists. This will prevent any possible issues or crashes if the class does not exist.

• Introduced new 'ReplicateFormAction.php' file
  We have added a new file called src/Filament/Actions/ReplicateFormAction.php. This file includes a fresh class ReplicateFormAction that follows the ReplicatesRecords format. This particular class enhances the action process with the addition of an icon, label and form fields for better user experience.

• Updated 'FormResource.php' with 'ReplicateFormAction'
  In src/Filament/Resources/FormResource.php, the old 'ReplicateAction' has been replaced by the more efficient ReplicateFormAction class, increasing the performance of the form resource.