Resolve "Allow Automatic Field Widget Action"

Closes #3578437

Manual test steps

• Go to Structure → Content types → [type] → Manage form display
• Add any field widget action (e.g., "Fill plain text" test action)
• Enable the action and check the new Automatic checkbox → Save
• Navigate to the node add/edit form
• Verify the action fires automatically on form load (the AJAX callback is triggered without clicking the button)
• Uncheck Automatic → Save → Confirm the action only fires on manual button click