fix: fix PaLM not working issue (#667)

* bugfix for #515 最新版本谷歌PaLM模型无法使用

* update

* chore: remove unrelated file

* chore: add comment

---------

Co-authored-by: JustSong <songquanpeng@foxmail.com>

controller/relay-text.go

@@ -367,6 +367,8 @@ func relayTextHelper(c *gin.Context, relayMode int) *OpenAIErrorWithStatusCode {
 			}
 		case APITypeTencent:
 			req.Header.Set("Authorization", apiKey)
+		case APITypePaLM:
+			// do not set Authorization header
 		default:
 			req.Header.Set("Authorization", "Bearer "+apiKey)
 		}