message: fix(plugins-flow-client): add button style before return type tiles
diff: <div *ngIf="tile.type === tileTypes.Task" class="tile--group">
  <flogo-diagram-tile-insert
  @tileInsert
  - class="tile--slot tile__add-between"
  + class="tile__add-between"
  [hidden]="hideInsertTile(tile.task?.id)"
  [tile]="tile"
  [currentSelection]="selection"
  + [insertBetween]="true"
  (select)="onInsertSelected($event)"
  ></flogo-diagram-tile-insert>
  <flogo-diagram-tile-task
  