Addons-server: "View Site" returns a 500

[ioanarusiczki]

From https://github.com/mozilla/addons-server/issues/11321

STR:

1. Go to django admin pages and click one of the reports from AMO Administration
2. There is a "View site" button on the top right corner
3. Click on it

Expected result:
Perhaps https://addons-internal.dev.mozaws.net/en-US/admin/ should be displayed - the Menu for admin tools.

Actual result:
URL is https://addons-internal.dev.mozaws.net/en-US/firefox/ with a 500 error.

Notes:
This is reproducible on both django dev and stage - FF66(WIN10).

[diox]

Ah so this time it's the global view site in the admin... It's kinda useful, so instead of removing that one we should just override it to use the right setting (EXTERNAL_SITE_URL I think?) instead of /.

[ioanarusiczki]

@diox Verified on dev with FF69(Win10).