fix:Add loader to artifact search bar

[rsanteri]

Description of the Change

Add loader to artifact search input field.

[saikonen]

looks good. Just leaving a note in case an actual progress bar is also requested that the artifact search also provides progress info on the search process via

{
  "type": "progress",
  "fraction": number
}

where the number will be a fraction of (current idx)/(number of artifacts affected by searchterm)

For now I believe that a simple spinner is more than enough though.