add support for TogetherAI (#1890)

### What problem does this PR solve?

#1853 add support for TogetherAI

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Zhedong Cen <cenzhedong2@126.com>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

web/src/pages/user-setting/setting-model/constant.ts

@@ -25,6 +25,7 @@ export const IconMap = {
   'OpenAI-API-Compatible': 'openai-api',
   cohere: 'cohere',
   Lepton: 'lepton',
+  TogetherAI:'together-ai',
   PerfXCould: 'perfx-could'
 };