[ios-clr] Update Subsets.props to build CoreCLR subset for Apple mobile (#120787)

## Description

When CoreCLR runtime packs were enabled in
#120444, the `clr` subset isn't
being built by default for Apple mobile targets. This issue wasn’t
caught before because the CI builds are using the `clr+packs` command.

Author: kotlarmilos

eng/Subsets.props

@@ -73,7 +73,7 @@
     <DefaultSubsets Condition="'$(TargetsMobile)' == 'true'">mono+libs+packs</DefaultSubsets>
     <DefaultSubsets Condition="'$(TargetsAndroid)' == 'true' and '$(CoreCLRSupported)' == 'true'">clr+mono+libs+host+packs</DefaultSubsets>
     <DefaultSubsets Condition="'$(TargetsAndroid)' == 'true' and '$(CoreCLRSupported)' != 'true' and '$(NativeAotSupported)' == 'true'">clr.nativeaotruntime+clr.nativeaotlibs+mono+libs+packs</DefaultSubsets>
-    <DefaultSubsets Condition="'$(TargetsAppleMobile)' == 'true'">clr.nativeaotruntime+clr.nativeaotlibs+mono+libs+packs</DefaultSubsets>
+    <DefaultSubsets Condition="'$(TargetsAppleMobile)' == 'true'">clr+mono+libs+host+packs</DefaultSubsets>
     <DefaultSubsets Condition="'$(TargetsLinuxBionic)' == 'true' and '$(MonoSupported)' == 'true'">clr.nativeaotruntime+clr.nativeaotlibs+mono+libs+host+packs</DefaultSubsets>
     <DefaultSubsets Condition="'$(TargetsLinuxBionic)' == 'true' and '$(MonoSupported)' != 'true'">clr.nativeaotruntime+clr.nativeaotlibs+libs+packs</DefaultSubsets>
     <!-- In source build, mono is only supported as primary runtime flavor. -->
@@ -99,6 +99,7 @@
   <PropertyGroup Condition="'$(RuntimeFlavor)' == ''">
     <RuntimeFlavor Condition="('$(TargetsMobile)' == 'true' or '$(TargetsLinuxBionic)' == 'true') and ($(_subset.Contains('+clr.nativeaotlibs+')) or $(_subset.Contains('+clr.runtime+')))">CoreCLR</RuntimeFlavor>
     <RuntimeFlavor Condition="'$(TargetsAndroid)' == 'true' and ($(_subset.Contains('+clr+')) or $(_subset.Contains('+clr.')))">CoreCLR</RuntimeFlavor>
+    <RuntimeFlavor Condition="'$(TargetsAppleMobile)' == 'true' and ($(_subset.Contains('+clr+')) or $(_subset.Contains('+clr.')))">CoreCLR</RuntimeFlavor>
     <RuntimeFlavor Condition="'$(TargetsBrowser)' == 'true' and ($(_subset.Contains('+clr+')) or $(_subset.Contains('+clr.')))">CoreCLR</RuntimeFlavor>
     <RuntimeFlavor Condition="'$(RuntimeFlavor)' == '' and '$(TargetsMobile)' == 'true'">Mono</RuntimeFlavor>
     <RuntimeFlavor Condition="'$(RuntimeFlavor)' == '' and ($(_subset.Contains('+mono+')) or $(_subset.Contains('+mono.runtime+'))) and (!$(_subset.Contains('+clr+')) and !$(_subset.Contains('+clr.runtime+')) and !$(_subset.Contains('+clr.corelib+')))">Mono</RuntimeFlavor>
@@ -109,6 +110,7 @@
     <DefaultCoreClrSubsets>clr.native+clr.corelib+clr.tools+clr.nativecorelib+clr.packages+clr.nativeaotlibs+clr.crossarchtools+host.native</DefaultCoreClrSubsets>
     <DefaultCoreClrSubsets Condition="'$(TargetRid)' == 'linux-armel'">clr.native+clr.corelib+clr.tools+clr.nativecorelib+clr.packages+clr.nativeaotlibs+clr.crossarchtools</DefaultCoreClrSubsets>
     <DefaultCoreClrSubsets Condition="'$(TargetsAndroid)' == 'true'">clr.native+clr.corelib+clr.tools+clr.nativecorelib+clr.packages+clr.nativeaotlibs+clr.crossarchtools</DefaultCoreClrSubsets>
+    <DefaultCoreClrSubsets Condition="'$(TargetsAppleMobile)' == 'true'">clr.native+clr.corelib+clr.tools+clr.nativecorelib+clr.packages+clr.nativeaotlibs+clr.crossarchtools</DefaultCoreClrSubsets>
     <DefaultCoreClrSubsets Condition="'$(TargetsBrowser)' == 'true'">mono.emsdk+clr.native+clr.corelib+clr.tools+clr.packages+clr.crossarchtools</DefaultCoreClrSubsets>
     <!-- Even on platforms that do not support the CoreCLR runtime, we still want to build ilasm/ildasm. -->
     <DefaultCoreClrSubsets Condition="'$(RuntimeFlavor)' != 'CoreCLR'">clr.iltools+clr.packages</DefaultCoreClrSubsets>