fdo#84376 Add missing title to the Template Manager dialog

Change-Id: I514cc4354950119caa4c16d0ccb6b9d18290dee3
Reviewed-on: https://gerrit.libreoffice.org/11659
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>