Replace deprecated text-moderation model

Problem/Motivation

In April, OpenAI announced the deprecation of the following text-moderation models in the API:

• text-moderation-007
• text-moderation-stable
• text-moderation-latest

Access to these models in the API ended on October 27, 2025.

Proposed resolution

OpenAI recommended switching to the new omni-moderation model. This can be accomplished with a simple patch. I've tested this on one of my sites that relies on OpenAI text moderation, and it works.