Used limited reader in user invite (#25943)

* Used limited reader in user invite

* Added tests

server/public/model/utils.go

@@ -553,6 +553,16 @@ func StringInterfaceFromJSON(data io.Reader) map[string]any {
 	return objmap
 }
 
+func StructFromJSONLimited[V any](data io.Reader, maxBytes int64, obj *V) error {
+	lr := io.LimitReader(data, maxBytes)
+	err := json.NewDecoder(lr).Decode(&obj)
+	if err != nil || obj == nil {
+		return err
+	}
+
+	return nil
+}
+
 // ToJSON serializes an arbitrary data type to JSON, discarding the error.
 func ToJSON(v any) []byte {
 	b, _ := json.Marshal(v)