I design for a large company and we need to make sure that everything tests fine against 508 compliance, which includes color conflicts for color blindness and deficiencies. Is there an easy way to turn ON/OFF a switch to test for this?
We don't currently have anything built in to help you with that. I think that's a good idea and would recommend that you head on over to our UserVoice feature request page: Adobe XD: Feature Requests: Top (415 ideas) – Adobe XD Feedback : Feature Requests & Bugs and suggest it.
In the meantime, googling for terms like "color blindness simulation tools" yields what look like some pretty workable solutions external to any particular app.