Bug 30768: Capitalizing "pin" in 2FA setup

Bug 30768: Capitalizing "pin" in 2FA setup

Change of text from "pin" to "PIN" in the 2FA setup interface.
This slight changes clarifies that "PIN" is an acronym,
 and increases user comprehension

To test:
1) Log in as an Administrator
2) Enable TwoFactorAuthentication
3) Log in to a user with superlibrarian permissions.
4) On the user profile page, click the "More" dropdown button,
click "Manage Two-Factor
5) Check that "pin" is displayed in lowercase, in both instances.
6) Apply patch.
7) Refresh the page and observe that "pin" has changed to "PIN"
8) Sign off.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>