databases/mysql84-{client,server}: Update to 8.4.11

This release contains the security fixes of the Oracle Critical
Patch Update of July 2026. 31 of the 54 MySQL issues apply to the
8.4 series and to the MySQL Router built from this port.

Changes:
https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-4-11.html

Security: 10f5d195-90a5-11f1-bc30-3497f65b111b
Sponsored by: Netzkommune GmbH

(cherry picked from commit 335950b823a1ad33d6f2bc20f869df46c2c624b7)