fix: fallback to original dataset VR for XS

Co-authored-by: Davide Punzo <punzodavide@hotmail.it>

platform/core/src/classes/MetadataProvider.js

@@ -20,6 +20,7 @@ class MetadataProvider {
       writable: false,
       value: new Map(),
     });
+    this.datasets = {};
   }
 
   async addInstance(dicomJSONDatasetOrP10ArrayBuffer, options = {}) {
@@ -52,6 +53,7 @@ class MetadataProvider {
       SOPInstanceUID,
     } = naturalizedDataset;
 
+    this._getAndCacheStudyDataset(StudyInstanceUID, dicomJSONDataset);
     const study = this._getAndCacheStudy(StudyInstanceUID);
     const series = this._getAndCacheSeriesFromStudy(study, SeriesInstanceUID);
     const instance = this._getAndCacheInstanceFromStudy(series, SOPInstanceUID);
@@ -71,6 +73,16 @@ class MetadataProvider {
     this.imageIdToUIDs.set(imageId, uids);
   }
 
+  _getAndCacheStudyDataset(StudyInstanceUID, dataset) {
+    if (!this.datasets[StudyInstanceUID]) {
+      this.datasets[StudyInstanceUID] = dataset;
+    }
+  }
+
+  getStudyDataset(StudyInstanceUID) {
+    return this.datasets[StudyInstanceUID];
+  }
+
   _getAndCacheStudy(StudyInstanceUID) {
     const studies = this.studies;
 
@@ -83,6 +95,7 @@ class MetadataProvider {
 
     return study;
   }
+
   _getAndCacheSeriesFromStudy(study, SeriesInstanceUID) {
     let series = study.series.get(SeriesInstanceUID);