MistalAI: Add custom stop strings

Closes #3627

public/scripts/openai.js

@@ -2072,6 +2072,7 @@ async function sendOpenAIRequest(type, messages, signal) {
 
     if (isMistral) {
         generate_data['safe_prompt'] = false; // already defaults to false, but just incase they change that in the future.
+        generate_data['stop'] = getCustomStoppingStrings(); // Mistral shouldn't have limits on stop strings.
     }
 
     if (isCustom) {

src/endpoints/backends/chat-completions.js

@@ -586,6 +586,7 @@ async function sendMistralAIRequest(request, response) {
             'stream': request.body.stream,
             'safe_prompt': request.body.safe_prompt,
             'random_seed': request.body.seed === -1 ? undefined : request.body.seed,
+            'stop': Array.isArray(request.body.stop) && request.body.stop.length > 0 ? request.body.stop : undefined,
         };
 
         if (Array.isArray(request.body.tools) && request.body.tools.length > 0) {