www/forgejo-lts: Correct AppWorkPAth

We were incorrectly setting AppWorkPath to DATADIR and creating DATADIR
on installation. Set it to DBDIR instead to match the app.ini and rc
script we generate. This should be a nop for anyone with a working
configuration, and should allow forgejo-cli to work without explicitly
specifying the correct work directory.

PR: 294619
MFH: 2026Q2
(cherry picked from commit 7c546a3a09e0e09f2fa1e5695057410e52a15dfb)