GPL-933 Housekeeping - Add integration test for submissions interface

[JamesGlover]

Describe the Housekeeping The submissions interface is lacking in a good integration test. Given its complexity it would be a good idea to add this.

Blocking issues Describe any other issues or tickets that may be blocking this change.

Additional context

• Test the basic submission interface
• Use user with lowest possible privileges
• Test JS, so full integration testing mode
• Don't need to exhaustively test all possibilities, but makes sure we use a complicated enough submission template as an example.