refactor: adjust font size of rbt-input-multi to improve UI consistency

apps/app/src/features/openai/client/components/AiAssistant/AiAssistantManagementModal/AiAssistantManagementKeywordSearch.module.scss

@@ -5,7 +5,7 @@
 .grw-ai-assistant-keyword-search :global {
   .rbt {
     .rbt-input-multi {
-      font-size: 1.4rem;
+      font-size: 1.2rem;
       border: none;
       border-bottom: 3px solid bs.$gray-200;
       border-radius: 0;