chore: some small improvements (#223)

* chore: stylize error message div
chore: correct styles for sidebar btn
chore: add spinner and replace header "Please wait" on spinner
chore: correct Russian translate
chore: hide clear conversation btn if not conversations
chore: stylize "Need OpenAI key" div

* chore: corrent Russian translate

components/Sidebar/ClearConversations.tsx

@@ -18,7 +18,7 @@ export const ClearConversations: FC<Props> = ({ onClearConversations }) => {
   };
 
   return isConfirming ? (
-    <div className="flex w-full cursor-pointer items-center rounded-md py-3 px-3 hover:bg-[#343541]">
+    <div className="flex w-full cursor-pointer items-center rounded-lg py-3 px-3 hover:bg-gray-500/10">
       <IconTrash size={18} />
 
       <div className="ml-3 flex-1 text-left text-[12.5px] leading-3 text-white">