Revert "copilot: Correct o3-mini context length" (#24275)

Reverts zed-industries/zed#24152
See comment: https://github.com/zed-industries/zed/pull/24152#issuecomment-2636808170
Manually confirmed >20k generates error.
992125bec2Peter Tripp committed on 2/5/2025, 3:03:45 PM· committed by GitHubparent74c4dbd
1 file changedLine totals unavailable