Fix missing translation in pagination gap tags (#24262)

Co-authored-by: Eugen Rochko <eugen@zeonfederated.com>

app/views/kaminari/_gap.html.haml

+-#
+  Non-link tag that stands for skipped pages...
+  available local variables
+    current_page:  a page object for the currently displayed page
+    total_pages:   total number of pages
+    per_page:      number of items to fetch per page
+    remote:        data-remote
+%span.page.gap
+  != t('pagination.truncate')