Fix UseGalaxy download button redirect

[hujambo-dunia]

• Should automatically redirect user after they see the "You're About to Be Redirected" landing page
• Currently, the user can still manually click from the list of 3+ usegalaxy.* sites but not ideal

[hexylena]

to clarify my comment in matrix: i don't want to see the redirect page at all, I want to click "galaxy eu" and go directly to that site. I don't understand waiting 5 seconds for this needless intermediate redirect. And for "other" I think it really should redirect to /use/ rather than this custom redirect page.