databases/mongodb70: 7.0.31

Announcement:
https://www.mongodb.com/community/forums/t/mongodb-7-0-31-is-released/337038?u=r_k

Release Notes:
https://www.mongodb.com/docs/manual/release-notes/7.0/#7.0.31---mar-17--2026

Security: CVE-2026-4147 Stack memory disclosure in filemd5 command
Security: CVE-2026-4148 ExpressionContext use-after-free in classic engine $lookup and $graphLookup aggregation operators