fix: infra token expriry check on guard (#4219)

fix: null check added in infraToken expiry check on guard

packages/hoppscotch-backend/src/guards/infra-token.guard.ts

@@ -38,7 +38,7 @@ export class InfraTokenGuard implements CanActivate {
       throw new UnauthorizedException(INFRA_TOKEN_INVALID_TOKEN);
 
     const currentTime = DateTime.now().toISO();
-    if (currentTime > infraToken.expiresOn.toISOString()) {
+    if (currentTime > infraToken.expiresOn?.toISOString()) {
       throw new UnauthorizedException(INFRA_TOKEN_EXPIRED);
     }