multimedia/gmp-api: update to Firefox135 release

This was released on 2023-04-17 and is a requisite for updating
OpenH264.

Changelog: "Updates to enable features in OpenH264 for improved decoding
performance." https://github.com/mozilla/gmp-api/releases/tag/Firefox135

PR: 288375
Approved by: ports-secteam@ (fernape@)
MFH: 2025Q3