multimedia/py-subliminal: Fine tune dependencies

subliminal requires knowit>=0.5.5 and defusedxml>=0.7.1 at run time,
but the port only lists them in TEST_DEPENDS

The patch moves them to RUN_DEPENDS and updates the port to 2.8.0:

• 2.8.0 requires typing-extensions>=4.10;
• the other RUN_DEPENDS minimums follow 2.8.0's requirements; enzyme and tomli, which nothing imports, are dropped (enzyme is a knowit provider); rarfile (the rar extra) stays for RAR support

PR: 299480
MFH: 2026Q4
(cherry picked from commit 8c2a499592df546a223bf142f17b559ed13e5d46)