Gemma 4 renderer "nothink" case fixed

A rendering issue in the Gemma 4 model support has been addressed. The previous attempt to fix how the renderer handles cases where thinking is disabled—known as the "nothink" case—was producing incorrect output by inserting unwanted thought channels. That change has been reverted and replaced with a cleaner solution: a dedicated e2b-style chat template that correctly formats prompts when thinking is not enabled. The new template handles the nuances of thought channel rendering without the bugs introduced by the earlier approach.