Generate Ensemble Statistics can fail if the initial data is NOT read from a .dream3d file

If a pipeline starts by reading an EBSD file and proceeds through the reconstruction and statistics phases and then a user attempts to use the "Generate Ensemble Statistics" filter they will be unable to select the phase types because that information is not available. If the initial data is read from a .dream3d file then the number of phases is known because we are reading a know array from the file.

先重現所描述的 pipeline：讀取一個 EBSD 檔案，執行重建和統計，然後開啟 Generate Ensemble Statistics 篩選器。檢查此篩選器如何取得相位資訊，並將其與從 .dream3d 檔案初始化的 pipeline 進行比較。在兩種情況下都可以選取相位類型，且不會破壞現有的 .dream3d 路徑，即表示完成。

由索引模型根據 Issue 內容生成。