[Fleet] Fix logic for detecting first time Elastic Agent users (#182214)

## Summary

Resolves #181800. Fixes the
logic for detecting first time Elastic Agent users on Cloud so that the
multi-page layout for adding an integration kicks in.

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/fleet/public/applications/integrations/sections/epm/screens/detail/hooks/use_is_first_time_agent_user.ts

@@ -51,6 +51,6 @@ export const useIsFirstTimeAgentUserQuery = (): UseIsFirstTimeAgentUserResponse
 
   return {
     isLoading: authz.fleet.readAgentPolicies && (areAgentPoliciesLoading || areAgentsLoading),
-    isFirstTimeAgentUser: !authz.fleet.readAgentPolicies && agents?.data?.total === 0,
+    isFirstTimeAgentUser: authz.fleet.readAgentPolicies && agents?.data?.total === 0,
   };
 };