Update draft-charter-2025.html

- Adds the open PR for web install into manifest

Author: diekus

charter/draft-charter-2025.html

@@ -505,7 +505,7 @@ <h3>
             </tr>
             <tr>
               <td>
-                <a href="#">Web Install API</a>
+                <a href="https://github.com/w3c/manifest/pull/1175">Web Install API</a>
               </td>
               <td>
                 An API to install web applications on the user's device.