Submitting certain forms result in blank pages

[niccofyren]

Seems like certain forms have at one point been converted from GET to POST, but still have leftover redirection logic.

Possible fixes:

• Make sure POST is done via JS and redirect clientside
• Make sure the resulting POST->GET page has links to navigate to the intended redirect page

We have fixed an instance of this in our running launch hotfix branch (af53a76, so feel free to use that as reference if needed) but is known to also exists for image reset as well, and probably other forms.