Move aspect processing before any clean up is started in change proce…

…ssing (#128)

While experimenting locally, I found out that
`IModelExporter.sourceDbChanges` is cleaned up before aspects are
processed. It doesn't brake existing strategies, but if another strategy
is added or package consumers add their own custom strategy it might
lead to bugs.

packages/transformer/src/IModelExporter.ts

@@ -356,6 +356,7 @@ export class IModelExporter {
     await this.exportFonts();
     await this.exportModelContents(IModel.repositoryModelId);
     await this.exportSubModels(IModel.repositoryModelId);
+    await this.exportAllAspects();
     await this.exportRelationships(ElementRefersToElements.classFullName);
 
     // handle deletes

packages/transformer/src/IModelTransformer.ts

@@ -2663,7 +2663,6 @@ export class IModelTransformer extends IModelExportHandler {
     // must wait for initialization of synchronization provenance data
     await this.exporter.exportChanges(this.getExportInitOpts(args));
     await this.processDeferredElements(); // eslint-disable-line deprecation/deprecation
-    await this.exporter["exportAllAspects"](); // eslint-disable-line @typescript-eslint/dot-notation
 
     if (this._options.optimizeGeometry)
       this.importer.optimizeGeometry(this._options.optimizeGeometry);