Current situation:
There was one scenario that was not described in T189130: Allow an empty namespace bar: When you select "search for filetype" and then select the "All" namespace preference twice, the "File" namespace is still in the namespace bar. You are able to remove it in the UI, but "under the hood" it will still be used and re-added as soon as you select another namespace.

Task:
Make the behavior consistent with the default namespace behavior as described in [T189130].

Acceptance Criteria:

• When "all" is selected and then deselected, the namespace tag should be visually removed but it stays active in the background as long as filetype is not "select a file type".
• As long as filetype is anything other than "select a filetype" add the namespace tag back after conducting the search.
• if the namespace tag gets removed after filetype is empty, don't add it back after search.