Bring back UnknownBody for UISIs

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

res/css/views/messages/_UnknownBody.scss

@@ -0,0 +1,16 @@
+/*
+Copyright 2015, 2016 OpenMarket Ltd
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_UnknownBody {
+    white-space: pre-wrap;
+}