Fix Usage Policy on DSS imagery.

DSS is not in public domain, but is only free for non-commercial uses
as of this writing at least. The following URL explains the Usage
Policy: https://archive.stsci.edu/data_use.html
3 jobs for !205 with user/akarsh/dss_url_fixes in 64 minutes and 50 seconds (queued for 94 minutes and 24 seconds)
detached
Status Job ID Name Coverage
  Build
passed #88575
build

00:06:05

 
  Test
passed #88576
build-and-test

00:50:29

passed #88577
build-appimage

00:08:14