feat: add adjustmentTimestamp to platformasset

mobile/ios/Runner/Sync/PHAssetExtensions.swift

@@ -12,7 +12,8 @@ extension PHAsset {
       height: Int64(pixelHeight),
       durationInSeconds: Int64(duration),
       orientation: 0,
-      isFavorite: isFavorite
+      isFavorite: isFavorite,
+      adjustmentTimestamp: adjustmentTimestamp
     )
   }
 
@@ -23,6 +24,10 @@ extension PHAsset {
   var filename: String? {
     return value(forKey: "filename") as? String
   }
+  
+  var adjustmentTimestamp: Int64 {
+    return (value(forKey: "adjustmentTimestamp") as? Date?).map( {Int64($0?.timeIntervalSince1970 ?? 0)} ) ?? 0
+  }
 
   // This method is expected to be slow as it goes through the asset resources to fetch the originalFilename
   var originalFilename: String? {