remove security docs

Author: kmurphypolygon

docs/learn/index.md

@@ -37,14 +37,6 @@ hide:
          </div>
          <p class="feature-paragraph">Driven by innovation, the Polygon type 1 prover is fully Ethereum equivalent.</p>
       </a>
-   </div>
-   <div class="grid-item">
-      <a href="./security/overview">
-         <div class="product-list-item-header">
-            <div class="feature-card-heading">Polygon security</div>
-         </div>
-         <p class="feature-paragraph">Polygon security, bug bounties, and more.</p>
-      </a>
    </div>
     <div class="grid-item">
       <a href="./plonky">