fix(frontend): Top Agents header spacing (#10002)

Changed the section header for "Top Agents" to include a 24px margin. 
I have not tested this, an eng needs to test / look at this

## Summary
- set `margin` default to 24px in `AgentsSection`
- apply the bottom margin via an inline style

## Testing
- `npm test` *(fails: playwright not found)*
- `npm run lint` *(fails: next not found)*


### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  - [x] Test via deployment to the dev branch and verify by designer

---------

Co-authored-by: Zamil Majdy <zamil.majdy@agpt.co>
Co-authored-by: Nicholas Tindle <nicholas.tindle@agpt.co>

autogpt_platform/frontend/src/components/agptui/composite/AgentsSection.tsx

@@ -32,7 +32,7 @@ export const AgentsSection: React.FC<AgentsSectionProps> = ({
   sectionTitle,
   agents: allAgents,
   hideAvatars = false,
-  margin = "37px",
+  margin = "24px",
 }) => {
   const router = useRouter();
 
@@ -48,11 +48,12 @@ export const AgentsSection: React.FC<AgentsSectionProps> = ({
   return (
     <div className="flex flex-col items-center justify-center">
       <div className="w-full max-w-[1360px]">
-        <div
-          className={`mb-[${margin}] font-poppins text-lg font-semibold text-[#282828] dark:text-neutral-200`}
+        <h2
+          style={{ marginBottom: margin }}
+          className="font-poppins text-lg font-semibold text-[#282828] dark:text-neutral-200"
         >
           {sectionTitle}
-        </div>
+        </h2>
         {!displayedAgents || displayedAgents.length === 0 ? (
           <div className="text-center text-gray-500 dark:text-gray-400">
             No agents found