[MM-32543] - Add ability to send email to admin that users are trying to invite others (#16882)

* [MM-32543] - Add ability to send email to admin that users are trying to join

* Update email template

* Feedback impl-1

* Fix test

* Feedback impl-2

* Fix error

* Feedback impl

* Use 413 status code

* make i18n-extract

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/client4.go

@@ -5972,3 +5972,13 @@ func (c *Client4) UpdateThreadFollowForUser(userId, teamId, threadId string, sta
 
 	return BuildResponse(r)
 }
+
+func (c *Client4) SendAdminUpgradeRequestEmail() *Response {
+	r, appErr := c.DoApiPost(c.GetCloudRoute()+"/subscription/limitreached/invite", "")
+	if appErr != nil {
+		return BuildErrorResponse(r, appErr)
+	}
+	defer closeBody(r)
+
+	return BuildResponse(r)
+}