Remove "Twitter" from AllowedExternalLinkReferences possible value list (#913)

When using GetPolicyInfoForPlayerAsync, the
AllowedExternalLinkReferences array no longer includes 'Twitter'.

## Changes

Removed "Twitter" from the list of possible values in the description
for AllowedExternalLinkReferences.

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Author: arxkdev

content/en-us/reference/engine/classes/PolicyService.yaml

@@ -55,7 +55,7 @@ methods:
       <td>AllowedExternalLinkReferences</td>
       <td>Array of strings</td>
       <td>Any experience that references external links</td>
-      <td>A list of external link references (for example, social media links, handles, or iconography) a player is permitted to see. Possible values include: "Discord", "Facebook", "Twitch", "Twitter", "YouTube", "X", "GitHub", and "Guilded".</td>
+      <td>A list of external link references (for example, social media links, handles, or iconography) a player is permitted to see. Possible values include: "Discord", "Facebook", "Twitch", "YouTube", "X", "GitHub", and "Guilded".</td>
       </tr>
       <tr>
       <td>IsContentSharingAllowed</td>