Added API to return user count bands and user count (#25796)

server/public/model/limits.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type UserLimits struct {
+	MaxUsersLimit      int64 `json:"maxUsersLimit"`      // max number of users allowed
+	LowerBandUserLimit int64 `json:"lowerBandUserLimit"` // user count for 1st warning
+	UpperBandUserLimit int64 `json:"upperBandUserLimit"` // user count for 2nd warning
+	ActiveUserCount    int64 `json:"activeUserCount"`    // actual number of active users on server. Active = non deleted
+}