Auto-generate crc64 package name when package is empty in XmlImporter

[Copilot]

• Understand the issue: When [Register("CustomView")] is used without a package prefix, the build fails because XmlImporter doesn't auto-generate a package name
• Review PR Add proper MSBuild error XA4238 for JCW XML import failures android#10717 and issue Register Attribute breaks build android#10653
• Analyze the code flow in java-interop
• Implement fix in XmlImporter.cs to auto-generate a package name when package is empty/missing
• Add GetPackageName(string ns, string assemblyName) overload to JavaNativeTypeManager for reuse
• Refactor existing GetPackageName overloads to use the new method
• Add test for the new behavior
• Run tests to validate the fix
• Add SetUp/TearDown to XmlImporterTests to save/restore PackageNamingPolicy

Summary

This PR fixes the issue where using [Register("CustomView")] without a package prefix would cause the build to fail in .NET 10. The fix auto-generates a package name from the partial assembly qualified name when the package attribute is empty or missing in the XML.

Changes

• Added JavaNativeTypeManager.GetPackageName(string ns, string assemblyName) public method that centralizes package name generation logic
• Refactored existing GetPackageName(Type) and GetPackageName(TypeDefinition, IMetadataResolver) to use the new method
• Updated XmlImporter.GeneratePackageFromAssemblyQualifiedName to use the new method instead of duplicating crc64 logic
• Added SetUp/TearDown methods to XmlImporterTests to properly save and restore PackageNamingPolicy

Original prompt

Review the PR:
@dotnet/android/pull/10717
And issue:
@dotnet/android/issues/10653

I think we need to do something in java-interop when the package is blank in these XML files -- to get back the previous behavior from .NET 9.

Did .NET 9 auto-generate a package name?

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[Copilot]

Pull request overview

This PR fixes a build failure in .NET 10 when using [Register("CustomView")] without a package prefix. The fix auto-generates a CRC64-based package name from the assembly-qualified type name when the package attribute is empty or missing in XML type definitions.

Changes:

• Added a new public GetPackageName(string ns, string assemblyName) method to JavaNativeTypeManager to centralize package name generation logic
• Refactored existing package name generation methods to use the new centralized method, reducing code duplication
• Enhanced XmlImporter to auto-generate package names when they're missing or empty

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
XmlImporterTests.cs	Comprehensive test suite covering package name generation for empty, missing, and explicit package scenarios, including edge cases like nested types and types without namespaces
JavaNativeTypeManager.cs	Adds new public method for package name generation and refactors existing overloads to use it, reducing code duplication while maintaining backward compatibility
XmlImporter.cs	Implements auto-generation of package names when missing/empty by parsing assembly-qualified names and delegating to JavaNativeTypeManager

[Copilot]

The tests in this class depend on JavaNativeTypeManager.PackageNamingPolicy being set to LowercaseCrc64, but they don't explicitly set or restore this value. If other tests modify this static property, these tests could fail. Consider adding SetUp and TearDown methods to save and restore the PackageNamingPolicy, similar to what JavaNativeTypeManagerTests does.

[jonathanpeppers]

@copilot can you follow your own suggestion here

[Copilot]

Added SetUp and TearDown methods to save and restore PackageNamingPolicy, following the pattern from JavaNativeTypeManagerTests. See commit 2feda94.