fix: Update Gemini safety settings category

relay/channel/gemini/constant.go

@@ -22,7 +22,7 @@ var ModelList = []string{
 
 var SafetySettingList = []string{
 	"HARM_CATEGORY_HARASSMENT",
-	"HARM_CATEGORY_VIOLENCE",
+	"HARM_CATEGORY_HATE_SPEECH",
 	"HARM_CATEGORY_SEXUALLY_EXPLICIT",
 	"HARM_CATEGORY_DANGEROUS_CONTENT",
 	"HARM_CATEGORY_CIVIC_INTEGRITY",