Set TrimMode partial by default (#7132)

Companion to dotnet/linker#2856

* Update src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets
* Remove more usages of TrimMode
* Update linker versions manually

Co-authored-by: Jonathan Peppers <jonathan.peppers@microsoft.com>

Author: agocke

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets

@@ -64,7 +64,9 @@
     <PublishTrimmed Condition=" '$(PublishTrimmed)' == '' and '$(Configuration)' == 'Release' and '$(AndroidLinkMode)' != 'None' ">true</PublishTrimmed>
     <AndroidLinkMode Condition=" '$(AndroidLinkMode)' == '' and '$(PublishTrimmed)' == 'true' ">SdkOnly</AndroidLinkMode>
     <AndroidLinkMode Condition=" '$(AndroidLinkMode)' == '' ">None</AndroidLinkMode>
-    <TrimmerDefaultAction Condition=" '$(TrimmerDefaultAction)' == '' and '$(AndroidLinkMode)' == 'Full' ">link</TrimmerDefaultAction>
+    <!-- For compat with user code not marked trimmable, only trim opt-in by default. -->
+    <TrimMode Condition=" '$(TrimMode)' == '' and '$(AndroidLinkMode)' == 'Full' ">link</TrimMode>
+		<TrimMode Condition="'$(TrimMode)' == ''">partial</TrimMode>
     <SuppressTrimAnalysisWarnings Condition=" '$(SuppressTrimAnalysisWarnings)' == '' ">true</SuppressTrimAnalysisWarnings>
     <!-- Prefer $(RuntimeIdentifiers) plural -->
     <RuntimeIdentifiers Condition=" '$(RuntimeIdentifier)' == '' And '$(RuntimeIdentifiers)' == '' ">android-arm;android-arm64;android-x86;android-x64</RuntimeIdentifiers>

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.ILLink.targets

@@ -28,17 +28,6 @@ This file contains the .NET 5-specific targets to customize ILLink
           Condition="'$(VSAndroidDesigner)' != ''"
           Value="$(VSAndroidDesigner)"
           Trim="true" />
-      <!-- Mark all assemblies to be linked for AndroidLinkMode=Full -->
-      <ResolvedFileToPublish
-          Update="@(ResolvedFileToPublish)"
-          Condition=" '$(AndroidLinkMode)' == 'Full' and '%(ResolvedFileToPublish.Extension)' == '.dll' and '%(ResolvedFileToPublish.AssetType)' != 'native' "
-          TrimMode="link"
-      />
-      <!-- TODO: remove setting the trim mode here, once the support packages are updated to NET6 and compatability packages not needed -->
-      <ResolvedFileToPublish
-          Condition=" '$(AndroidLinkMode)' == 'SdkOnly' and ( $([System.String]::Copy(%(Filename)).StartsWith ('Xamarin.AndroidX.')) or $([System.String]::Copy(%(Filename)).StartsWith ('Xamarin.Android.Support.')) or $([System.String]::Copy(%(Filename)).StartsWith ('Xamarin.Google.')) or $([System.String]::Copy(%(Filename)).StartsWith ('Xamarin.GooglePlayServices.')) ) ">
-        <TrimMode>link</TrimMode>
-      </ResolvedFileToPublish>
 
       <!--
         Used for the <ILLink CustomData="@(_TrimmerCustomData)" /> value: