Mitigate ITrackingItem.RawData == null issue (#362)

* Mitigate `ITrackingItem.RawData == null` issue

* Correct missing resources

Author: SergeiPavlov

Extensions/Xtensive.Orm.Tracking/Internals/TrackingItem.cs

@@ -37,15 +37,17 @@ public void MergeWith(ITrackingItem source)
         return;
       }
 
-      ArgumentNullException.ThrowIfNull(source.RawData);
-
       if (State == TrackingItemState.Created && source.State == TrackingItemState.Changed) {
+        ArgumentNullException.ThrowIfNull(source.RawData);
         State = TrackingItemState.Created;
         MergeWith(source.RawData.Difference);
         return;
       }
 
-      MergeWith(source.RawData.Difference);
+      if (source.RawData is not null) {
+        MergeWith(source.RawData.Difference);
+      }
+
       State = source.State;
     }
 

Version.props

@@ -2,7 +2,7 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
 <PropertyGroup>
-    <DoVersion>7.2.172</DoVersion>
+    <DoVersion>7.2.173</DoVersion>
     <DoVersionSuffix>servicetitan</DoVersionSuffix>
 </PropertyGroup>