Manage rules for mx_RoomView on _RoomView.pcss - _ScrollPanel.pcss (#10770)

* Move style rules of `mx_RoomView_MessageList` from _ScrollPanel.pcss on _RoomView.pcss

* Nesting: `mx_RoomView--local .mx_ScrollPanel`

res/css/_components.pcss

@@ -75,7 +75,6 @@
 @import "./structures/_RoomSearch.pcss";
 @import "./structures/_RoomStatusBar.pcss";
 @import "./structures/_RoomView.pcss";
-@import "./structures/_ScrollPanel.pcss";
 @import "./structures/_SearchBox.pcss";
 @import "./structures/_SpaceHierarchy.pcss";
 @import "./structures/_SpacePanel.pcss";

res/css/structures/_RoomView.pcss

@@ -181,11 +181,21 @@ limitations under the License.
     li {
         clear: both;
     }
+
+    .mx_ScrollPanel & {
+        position: relative;
+        display: flex;
+        flex-direction: column;
+        justify-content: flex-end;
+
+        content-visibility: auto;
+        contain-intrinsic-size: 50px;
     }
 
-.mx_RoomView--local .mx_ScrollPanel .mx_RoomView_MessageList {
+    .mx_RoomView--local .mx_ScrollPanel & {
         justify-content: center;
     }
+}
 
 li.mx_RoomView_myReadMarker_container {
     height: 0px;

res/css/structures/_ScrollPanel.pcss

@@ -1,27 +0,0 @@
-/*
-Copyright 2019 New Vector 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_ScrollPanel {
-    .mx_RoomView_MessageList {
-        position: relative;
-        display: flex;
-        flex-direction: column;
-        justify-content: flex-end;
-
-        content-visibility: auto;
-        contain-intrinsic-size: 50px;
-    }
-}