Renable import button when import process fail due to the namespace already been taken

Closes #19435

## Screenshots (if relevant)

Before:

![1](/uploads/e8de1b326e0751891f667630a7685f6a/1.png)<br/><br/>

After:

![2](/uploads/566f1fd5442c28232350689fce8eae76/2.png)

See merge request !5053
(cherry picked from commit d6efef0f)