CiviGrant - Add prefix to permission label

[colemanw]

Overview

Makes CiviGrant permissions easier to read on the Manage Permissions page.

Before

After

Comments

I think these prefixes were automatically added when CiviGrant was a component but now need to be manually added for the extension.

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).