message: resolved - matrix collapse-expand icon for vue
diff: question.getIsDetailPanelShowing(row) ? row.detailPanelId : null
  "
  >
  - <span :class="question.getDetailPanelIconCss(row)"></span>
  + <sv-svg-icon
  + :class="this.question.getDetailPanelIconCss(this.row)"
  + :iconName="this.question.getDetailPanelIconId(this.row)"
  + size="auto"
  + >
  + </sv-svg-icon>
  </button>
  </template>
  