Fix height jump of recording states

Fixes https://github.com/vector-im/element-web/issues/18431

res/css/views/rooms/_VoiceRecordComposerTile.scss

@@ -64,6 +64,10 @@ limitations under the License.
 .mx_MessageComposer_row .mx_VoiceMessagePrimaryContainer {
     // Note: remaining class properties are in the PlayerContainer CSS.
 
+    // fixed height to reduce layout jumps with the play button appearing
+    // https://github.com/vector-im/element-web/issues/18431
+    height: 32px;
+
     margin: 6px; // force the composer area to put a gutter around us
     margin-right: 12px; // isolate from stop/send button
 
@@ -83,7 +87,7 @@ limitations under the License.
             height: 10px;
             position: absolute;
             left: 12px; // 12px from the left edge for container padding
-            top: 16px; // vertically center (middle align with clock)
+            top: 17px; // vertically center (middle align with clock)
             border-radius: 10px;
         }
     }