fix: removed extra quotation mark in HTML class attribute

Corrected an HTML syntax error by removing a redundant quotation mark from a class attribute. This fixes the display issue for the IP card component, ensuring proper rendering of the IPv4 address section.

index.php

@@ -35,7 +35,7 @@ $ipv6_endpoint = "https://ipv6." . $domain;
     <main>
         <div class="container">
             <section class="ip-display">
-                <div class="ip-card"">
+                <div class="ip-card">
                     <h3>IPv4 Address</h3>
                     <p id="ipv4">
                         <iframe src="<?php echo $ipv4_endpoint; ?>" frameborder="0" width="100%" height="100%"></iframe>