Remove Field Search functionality

Summary:

We would like to know if it is possible to remove this "Search" option at the drop-down field.
This field is an added custom field using the Choice List (Dynamic) basing on the Contact at the Related Object field.
It is a field that filters the takes the list of employees.
We can search all employees in this field.

However, our issue is when the user clicks the "Search" option it will open a new window.
It will show that we can search (and create contacts), but we are not able to get any result.

Is there a way to remove the Search option?