Move iOS/tvOS simulator AOT imports in the Mono workload (#54821)

The condition on the import group for the iOS and tvOS simulators was not valid since iOS/tvOSSimulator is not a `TargetPlatformIdentifier`. To simplify, the simulator imports were moved under iOS/tvOS.

Fixes #53427

Co-authored-by: Steve Pfister <steve.pfister@microsoft.com>

src/mono/nuget/Microsoft.NET.Workload.Mono.Toolchain.Manifest/WorkloadManifest.targets

@@ -22,6 +22,7 @@
         <Import Project="Sdk.props" Sdk="Microsoft.NET.Runtime.RuntimeConfigParser.Task" />
         <Import Project="Sdk.props" Sdk="Microsoft.NETCore.App.Runtime.AOT.Cross.ios-arm" />
         <Import Project="Sdk.props" Sdk="Microsoft.NETCore.App.Runtime.AOT.Cross.ios-arm64" />
+        <Import Project="Sdk.props" Sdk="Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator" />
     </ImportGroup>
 
     <ImportGroup Condition="'$(TargetPlatformIdentifier)' == 'maccatalyst'">
@@ -32,15 +33,6 @@
     <ImportGroup Condition="'$(TargetPlatformIdentifier)' == 'tvos'">
         <Import Project="Sdk.props" Sdk="Microsoft.NET.Runtime.RuntimeConfigParser.Task" />
         <Import Project="Sdk.props" Sdk="Microsoft.NETCore.App.Runtime.AOT.Cross.tvos-arm64" />
-    </ImportGroup>
-
-    <ImportGroup Condition="'$(TargetPlatformIdentifier)' == 'iossimulator'">
-        <Import Project="Sdk.props" Sdk="Microsoft.NET.Runtime.RuntimeConfigParser.Task" />
-        <Import Project="Sdk.props" Sdk="Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator" />
-    </ImportGroup>
-
-    <ImportGroup Condition="'$(TargetPlatformIdentifier)' == 'tvossimulator'">
-        <Import Project="Sdk.props" Sdk="Microsoft.NET.Runtime.RuntimeConfigParser.Task" />
         <Import Project="Sdk.props" Sdk="Microsoft.NETCore.App.Runtime.AOT.Cross.tvossimulator" />
     </ImportGroup>