Add additional input validation for user creation (#11937)

api4/user.go

@@ -86,6 +86,8 @@ func createUser(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	user.SanitizeInput()
+
 	tokenId := r.URL.Query().Get("t")
 	inviteId := r.URL.Query().Get("iid")