[Event Hubs] Minor Organization and Formatting (Azure#25038)

The focus of these changes is to make a couple of small tweaks to project
organization and references.

Author: jsquire

sdk/eventhub/Azure.Messaging.EventHubs/Azure.Messaging.EventHubs.sln

@@ -91,6 +91,8 @@ Global
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{2CFDB3D6-5CFB-428C-9C89-29DD169B5433} = {2DB233D3-E757-423C-8F8D-742B0AFF4713}
+		{1C35D00F-F016-4ED1-98E6-813C6AE22E25} = {2DB233D3-E757-423C-8F8D-742B0AFF4713}
+		{5D38291E-D14C-4884-A902-9F9A470392BA} = {2DB233D3-E757-423C-8F8D-742B0AFF4713}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {509F2EE0-3348-4506-8AC7-9945B602CB43}

sdk/eventhub/Azure.Messaging.EventHubs/src/Azure.Messaging.EventHubs.csproj

@@ -13,7 +13,20 @@
     <Folder Include="Properties\" />
   </ItemGroup>
 
+  <!--
+    TEMP: This is needed for schema registry support and includes the IMessageWithContentType interface used
+          with EventData.
+  -->
   <ItemGroup>
+    <ProjectReference Include="..\..\..\core\Azure.Core.Experimental\src\Azure.Core.Experimental.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <!--
+      Restore when the experimental features needed are moved and published.
+
+      <PackageReference Include="Azure.Core" />
+    -->
     <PackageReference Include="Azure.Core.Amqp" />
     <PackageReference Include="Microsoft.Azure.Amqp" />
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" />
@@ -58,7 +71,4 @@
       <CustomToolNamespace>Azure.Messaging.EventHubs</CustomToolNamespace>
     </EmbeddedResource>
   </ItemGroup>
-  <ItemGroup>
-    <ProjectReference Include="..\..\..\core\Azure.Core.Experimental\src\Azure.Core.Experimental.csproj" />
-  </ItemGroup>
 </Project>