Bug 33875: Fix missing closing tag a in API key management page

Bug 33875: Fix missing closing tag a in API key management page

In API key management page, anchor closing tag is missing in message "No keys defined for the current patron".

This patch fixes that.
Also changes display with link on a new line.
Translatable text is on purpose surrounded by span or div.

Test plan :
1) Enable system preference  RESTOAuth2ClientCredentials
2) Go to a patron page
3) Click More > Manage API Keys
4) Look at page source HTML code
=> Check code is OK

Signed-off-by: Sam Lau <samalau@gmail.com>
Signed-off-by: David Cook <dcook@prosentient.com.au>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>