Data import settings page's 4th pane for File Extensions: Edit Action

Purpose: To be able to edit existing settings for handling various types of file extensions. This setting will allow a user to adjust whether an extension represents a particular type of file or files, and whether a file type should be excluded from data import. Users are allowed to edit system-supplied or user-created file extension settings.

Notes:
This story is very similar to UIDATIMP-56, which creates a new file extension setting. This story should be able to reuse much of what was built in UIDATIMP-56.
This story builds the edit screen and functionality. It is then connected to the UI's Edit buttons in the 4th pane via story UIDATIMP-69.

As a staff person
I want to be able to update settings related to file extensions for the Data Import app
So that they will be accurate

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)

Scenarios

1. Scenario 1
   • Given the Data Import Settings File extensions
   • When a User wants to update an existing file extension
   • Then they should be able to access an Edit file extension screen
2. Scenario 2
   • Given the Edit file extensions screen
   • When a User views the existing screen
   • Then it should appear as shown in the attached 08-Settings Edit file extension (block import).png or 07-Settings Edit file extension.png (do not block import).png
     • "Save" button at the top right of the header, which is greyed out until data has been filled in, then turns to blue once the screen is dirty (has some data in it)
     • Top of detail record: Edit [file extension]
     • Description: free text field, no length restriction
     • File extension: required field (asterisk next to the field name), should always start with a period
     • Block import section, with a "Block import" checkbox
     • Data type(s) section, which is required, and has a +Add button next to it (we may want to use the multi-select component instead, whichever you think is easier - options allowed are Delimited, EDIFACT, and/or MARC). A user must select one or more data types if Block import is not checked.
3. Scenario 3
   • Note: A user should not be allowed to check "Block import" AND Enter Data types. They should only be allowed to do one or the other.
   • Given the Edit file extensions screen
   • When a User attempts to check "Block Import" and Enter a data type
   • Then the screen should disallow the second thing to be entered until the first thing is deleted, e.g. no "data types" can be entered if "block import" is checked
4. Scenario 4
   • Given the Block import checkbox
   • If a user checks it
   • Then the "Data types" section should NOT be required and should be disabled on the screen
5. Scenario 5
   • Given the Edit file extensions screen
   • If a User has not filled in all required fields and presses the "Save" button
   • Then the record should not be saved
   • And the missing required data element(s) should be outlined in red, with the cursor in the data entry box for the first missing required element, along with the standard warning message, as shown in the attached Missing Required Data.PNG
6. Scenario 6
   • Given the Edit file extensions screen
   • If a User has filled in any data on the screen and begins to navigate away from it without creating/saving it
   • Then the user should see the standard modal asking whether they want to continue or not, as shown in the attached Unsaved changes modal.PNG
7. Scenario 7
   • Ensure automated testing coverage for this new code is 80% plus and confirm with screenshot