$(AndroidPackVersionSuffix)=preview.4; main is .NET 11 preview 4 (#10984)

Context: https://github.com/dotnet/android/tree/release/11.0.1xx-preview3

We branched for .NET 11 Preview 3 from d219840 into
`release/11.0.1xx-preview3`; the main branch is now .NET 11 Preview 4.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jonathanpeppers

Directory.Build.props

@@ -37,7 +37,7 @@
          * Bump first digit of the patch version for feature releases (and reset the first two digits to 0)
     -->
     <AndroidPackVersion>36.99.0</AndroidPackVersion>
-    <AndroidPackVersionSuffix>preview.3</AndroidPackVersionSuffix>
+    <AndroidPackVersionSuffix>preview.4</AndroidPackVersionSuffix>
     <!-- Final value set by GetXAVersionInfo target -->
     <IsStableBuild>false</IsStableBuild>
   </PropertyGroup>