Bug 1874253 - Remove firefoxview-next from static components manager r=fxview-reviewers,sclements

We have previously updated the AboutRedirector from `about:firefoxview-next` to `about:firefoxview`.
`firefoxview-next` no longer exists, so has been removed from the static components manager.

Differential Revision: https://phabricator.services.mozilla.com/D198815

Author: nikk15

browser/components/about/components.conf

@@ -14,7 +14,6 @@ pages = [
     'logins',
     'loginsimportreport',
     'firefoxview',
-    'firefoxview-next',
     'messagepreview',
     'newtab',
     'ion',