Missing language string warnings on Manage Repository page with MantisBT 2.25.0

[dregad]

When displaying a repository that has boolean values in its configuration (e.g. SVN), repo_manage_page.php triggers

APPLICATION WARNING 300: String "on" not found. (in '.../plugins/source-integration/Source/pages/repo_manage_page.php' line 62)
APPLICATION WARNING 300: String "off" not found. (in '.../plugins/source-integration/Source/pages/repo_manage_page.php' line 62)

These strings were removed in MantisBT 2.25.0 (see mantisbt/mantisbt#1702, mantisbt/mantisbt@4565713)