MFA login footer buttons reordered

Users going through multi-factor authentication were seeing buttons in the wrong sequence. The Back button appeared on the right side of the screen while Continue sat on the left — opposite of standard interface conventions where secondary actions precede primary ones.

The footer in the MFA view has been updated so Back appears before Continue in the DOM, placing it on the left where users expect to find a way to go back. The primary action button now sits on the right, its conventional position. This resolves the inconsistency reported in CX-45, aligning the login flow with established UI patterns across the application.