Add Secrets to game-settings.md (#845)

## Changes

<!-- Please summarize your changes. -->

Secrets can now be created and configured via the game settings security
menu for local studio sessions. This requires that HTTP requests be
allowed.

<!-- Please link to any applicable information (forum posts, bug
reports, etc.). -->


https://devforum.roblox.com/t/secrets-store-general-availability/2892154/72

## Checks

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- [x] This contribution was created in whole or in part by me, and I
have the right to submit it under the terms of this repository's open
source licenses.
- [x] I understand and agree that this contribution and a record of it
are public, maintained indefinitely, and may be redistributed under the
terms of this repository's open source licenses.
- [x] To the best of my knowledge, all proposed changes are accurate.

---------

content/en-us/studio/game-settings.md

@@ -147,6 +147,10 @@ You should only enable the following settings if you trust all assets from other
     <td>**Allow HTTP Requests**</td>
     <td>Allows experiences' servers to issue requests to remote servers via `Class.HttpService`.</td>
   </tr>
+  <tr>
+    <td>**Secrets**</td>
+    <td>Allows for the creation and configuration of [Secrets](../reference/engine/datatypes/Secret.yaml) for Studio sessions using `Class.HttpService`. Visible only if HTTP requests are allowed.</td>
+  </tr>
   <tr>
     <td>**Enable&nbsp;Studio&nbsp;Access to API Services**</td>
     <td>Lets Studio access API services. This setting is useful for testing the implementation of services like [data stores](../cloud-services/data-stores).</td>