Revert "Make the background-blur always 100%"

This reverts commit e8c974a.

Author: Dariusz Niemczyk

res/css/structures/_BackdropPanel.scss

@@ -31,6 +31,11 @@ limitations under the License.
     z-index: 0;
     pointer-events: none;
     overflow: hidden;
-    opacity: 0.2;
-    width: 100%;
+
+    &:nth-of-type(2n-1) {
+        opacity: 0.2;
+    }
+    &:nth-of-type(2n) {
+        opacity: 0.1;
+    }
 }

res/css/structures/_LeftPanel.scss

@@ -26,7 +26,6 @@ $roomListCollapsedWidth: 68px;
 .mx_LeftPanel_wrapper {
     display: flex;
     max-width: 50%;
-    position: relative;
 
     .mx_LeftPanel_background {