chore: remove 2_5

Author: margaritagomez

fern/assistants/pronunciation-dictionaries.mdx

@@ -48,7 +48,6 @@ Phoneme rules specify exact pronunciation using phonetic alphabets. These provid
 
 **Model Compatibility:**
 Phoneme rules only work with specific ElevenLabs models:
-- `eleven_turbo_v2_5`
 - `eleven_turbo_v2`
 - `eleven_flash_v2`