Avoid calling the user count query in future if we get a count > 0 (#23545)

* Avoid calling the user count query in future if we get a count > 0

* re-adding mock session to avoid adding the old mitigation in future

* adjustments based on feedback

server/channels/app/platform/service.go

@@ -49,10 +49,11 @@ type PlatformService struct {
 	sessionCache  cache.Cache
 	sessionPool   sync.Pool
 
-	asymmetricSigningKey atomic.Value
-	clientConfig         atomic.Value
-	clientConfigHash     atomic.Value
-	limitedClientConfig  atomic.Value
+	asymmetricSigningKey                   atomic.Value
+	clientConfig                           atomic.Value
+	clientConfigHash                       atomic.Value
+	limitedClientConfig                    atomic.Value
+	fetchUserCountForFirstUserAccountCheck atomic.Bool
 
 	logger              *mlog.Logger
 	notificationsLogger *mlog.Logger
@@ -126,6 +127,9 @@ func New(sc ServiceConfig, options ...Option) (*PlatformService, error) {
 		additionalClusterHandlers: map[model.ClusterEvent]einterfaces.ClusterMessageHandler{},
 	}
 
+	// Assume the first user account has not been created yet. A call to the DB will later check if this is really the case.
+	ps.fetchUserCountForFirstUserAccountCheck.Store(true)
+
 	// Step 1: Cache provider.
 	// At the moment we only have this implementation
 	// in the future the cache provider will be built based on the loaded config