databases/mongodb80: 8.0.29

Upstream changed the build tool from SCons to Bazel.
Please test before deploying to production.

Announcement:
https://www.mongodb.com/community/forums/t/mongodb-8-0-29-is-released/342426?u=r_k

Release Notes:
https://www.mongodb.com/docs/manual/release-notes/8.0/#8029---aug-11-2026