graphics/openexr*: security update to 3.4.3

Changelog: https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.3
Security: c71a3914-ba96-11f0-aada-f59a8ea34d12
MFH: 2025Q4
(cherry picked from commit 2dc4c91ea529203b893086d7c06a756a0e1f779e)
(cherry picked from commit c0f85663f34f29c0e9013f9c35ced11620a408c5)

Includes this commit:

graphics/openexr: Fix build with openjph 0.23.0+ [by sunpoet@]

• Add BUILD_DEPENDS check

Approved by: portmgr (blanket)
Obtained from: https://github.com/AcademySoftwareFoundation/openexr/pull/2122

(cherry picked from commit 3325dbe6f13323cd0eeeed35d03d045e2e413881)