Update links to be acm.gg instead of go.acm (#365)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Chores**
* Updated external shortlinks across the application to new unified
domains. Affected links include Discord invitations, reimbursement
submissions, SIG pizza signups, and member access request support pages.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: devksingh4

src/api/functions/ses.ts

@@ -226,7 +226,7 @@ export function generateSalesEmail(
             If you have any questions, feel free to ask on our Discord!
         </p>
         <div style="text-align: center; margin-top: 20px;">
-            <a href="https://go.acm.illinois.edu/discord" class="button">Join our Discord</a>
+            <a href="https://acm.gg/discord" class="button">Join our Discord</a>
         </div>
     </div>
     <div class="footer">

src/ui/components/AppShell/index.tsx

@@ -121,13 +121,13 @@ export const navItems = [
 
 export const extLinks = [
   {
-    link: "https://go.acm.illinois.edu/reimburse",
+    link: "https://acm.gg/reimburse",
     name: "Funding and Reimbursement Requests",
     icon: IconFileDollar,
     description: null,
   },
   {
-    link: "https://go.acm.illinois.edu/sigpizza",
+    link: "https://acm.gg/sigpizza",
     name: "Pizza Request Form",
     icon: IconPizza,
     description: null,

src/ui/components/AuthGuard/index.tsx

@@ -211,10 +211,8 @@ export const AuthGuard: React.FC<
           <Title>Unauthorized</Title>
           <Text>
             You have not been granted access to this module. Please fill out the{" "}
-            <a href="https://go.acm.illinois.edu/access_request">
-              access request form
-            </a>{" "}
-            to request access to this module.
+            <a href="https://acm.gg/access_request">access request form</a> to
+            request access to this module.
           </Text>
           <Card withBorder>
             <Title order={3} mb="md">