Bump to .NET 6.0.100-alpha.1.21064.27 (dotnet#5504)

Changes: dotnet/installer@efac3f2...47153b5

We are hitting a problem inside Visual Studio, where our .NET 6
projects aren't able to build:

	NETSDK1147: The following workload packs were not installed: Microsoft.Android.Sdk

`dotnet build` worked fine, but not inside the IDE.
Updating .NET 6 solves this issue.

We haven't updated our build of .NET 6 since ~Nov 13; let's update!

Additionally the contents of `$(_ExtraTrimmerArgs)` needs to be
altered so that `--dump-dependencies` is *first*, not last.
The previous ordering would result in an IL1015 error with the latest
.NET 6 bits:

	ILLink : error IL1015: Unrecognized command-line option: '--dump-dependencies

Reordering `$(_ExtraTrimmerArgs)` avoids the IL1015 error.

Co-authored-by: Radek Doulik <radekdoulik@gmail.com>

Configuration.props

@@ -72,7 +72,7 @@
     <DotNetPreviewTool Condition=" '$(DotNetPreviewTool)' == '' ">$(DotNetPreviewPath)dotnet</DotNetPreviewTool>
     <!-- Version number from: https://github.com/dotnet/installer#installers-and-binaries -->
     <DotNetPreviewVersionBand Condition=" '$(DotNetPreviewVersionBand)' == '' ">6.0.100</DotNetPreviewVersionBand>
-    <DotNetPreviewVersionFull Condition=" '$(DotNetPreviewVersionFull)' == '' ">$(DotNetPreviewVersionBand)-alpha.1.20562.2</DotNetPreviewVersionFull>
+    <DotNetPreviewVersionFull Condition=" '$(DotNetPreviewVersionFull)' == '' ">$(DotNetPreviewVersionBand)-alpha.1.21064.27</DotNetPreviewVersionFull>
     <WixToolPath Condition=" '$(WixToolPath)' == '' ">$(AndroidToolchainDirectory)\wix\</WixToolPath>
     <AndroidCmakeVersion Condition=" '$(AndroidCmakeVersion)' == '' ">3.10.2</AndroidCmakeVersion>
     <AndroidCmakeVersionPath Condition=" '$(AndroidCmakeVersionPath)' == '' ">$(AndroidCmakeVersion).4988404</AndroidCmakeVersionPath>

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

@@ -61,7 +61,7 @@ This file contains the .NET 5-specific targets to customize ILLink
     </PropertyGroup>
     <PropertyGroup
         Condition=" '$(LinkerDumpDependencies)' == 'true' ">
-      <_ExtraTrimmerArgs>$(_ExtraTrimmerArgs) --dump-dependencies"</_ExtraTrimmerArgs>
+      <_ExtraTrimmerArgs>--dump-dependencies $(_ExtraTrimmerArgs)"</_ExtraTrimmerArgs>
     </PropertyGroup>
     <ItemGroup>
       <!-- add our custom steps -->