Remove float property to let the margin between events appear on bubble message layout (#8373)

* Add margin between events on bubble message layout

Signed-off-by: Suguru Hirahara <luixxiul@users.noreply.github.com>

* Use more simplified way

Because the float property prevents the margin from appearing, removing
the property is more straightforward than adding other rules.

Signed-off-by: Suguru Hirahara <luixxiul@users.noreply.github.com>

Co-authored-by: Kerry <kerrya@element.io>

Author: luixxiul

res/css/views/rooms/_EventBubbleTile.scss

@@ -154,7 +154,7 @@ limitations under the License.
 
     &[data-self=true] {
         .mx_EventTile_line {
-            float: right;
+            margin-inline-start: auto;
             border-bottom-left-radius: var(--cornerRadius);
 
             .mx_MImageBody .mx_MImageBody_thumbnail_container,