Data import settings page's 3rd pane for File Extensions: Header Caret Action

Purpose: To define the actions of the Header caret in the Data Import Settings File Extensions header pane, except for the + New button (separate story for it).

As a staff person
I want to be able to take actions on one or more file extension settings in my file extension results list
So that I can easily work with these settings from the results list, rater than the individual extension detail screen.

Live prototype:
https://xd.adobe.com/view/0bb2d8ab-aabd-4ff6-4d5a-faa59a93368e-7d83/

Brief video walk-through
https://www.dropbox.com/s/3slcv4v49qm92rv/2018-11-06-data-import-19.mp4?dl=0 (see 4:10-5:10 in the video)

Waiting on revised wireframes from Filip showing blocked format in extension list and cards

Scenarios

1. Scenario 1
   • Given the File extensions third pane in the Data Import Settings (as shown in attachment 04-Settings File extensions.png)
   • When a User clicks the down caret next to the File extensions header
   • Then they should see a button that says "Reset all extension mappings to system defaults" (as shown in attachment 11-Settings file extensions options.png
2. Scenario 2
   • Given the Reset all extension mappings... button
   • When a user clicks that button
   • Then FOLIO should display the modal as shown in attachment 12-Settings file extensions reset modal.png
3. Scenario 3
   • Given the Reset all extension modal
   • When the User clicks Cancel
   • Then the modal should close without deleting any user-defined extensions or resetting any system-supplied extensions.
4. Scenario 4
   • Given the Reset all extension modal
   • When the User clicks Reset all
   • Then the modal should close
   • And any user-input file extensions should be deleted
   • And any system-supplied default file extensions should be reset to their default settings (recreated if deleted by a user, set back to their original settings if edited by a user)
   • And the file extensions 3rd pane should basically look like it did the first time it was displayed in the tenant, before any edits were made by any users
5. Scenario 5
   • Ensure automated testing coverage for this new code is 80% plus and confirm with screenshot

NOTE: blocked until backend work is done to create data schema and APIs