Document ReportShared object removal in migration guide

- Add detailed migration instructions for ReportShared removal
- Clarify that name and status remain on parent Report object
- Show that other properties moved to specific report type accessors
- Include example showing document report accessor usage

Author: dvacca-onfido

MIGRATION.md

@@ -37,6 +37,24 @@ ensuring a smooth transition between versions.
 ### Other Endpoints
 
 - Reports
+  - **`ReportShared` object removed**: Common report properties previously accessed
+    via `getReportShared()` are now available directly on each specific report type
+    - Example migration:
+
+      ```java
+      // Before (v6.x)
+      ReportName name = report.getReportShared().getName();
+      ReportStatus status = report.getReportShared().getStatus();
+      String checkId = report.getReportShared().getCheckId();
+      String result = report.getReportShared().getResult();
+
+      // After (v7.x)
+      ReportName name = report.getName(); // Still on parent Report object
+      ReportStatus status = report.getStatus(); // Still on parent Report object
+      String checkId = report.getDocumentReport().getCheckId(); // E.g. for document report
+      String result = report.getDocumentReport().getResult(); // E.g. for document report
+      ```
+
   - Device Intelligence: Removed deprecated `breakdown` property and related
     breakdown classes:
     - `DeviceIntelligenceBreakdownProperties` removed