This pull request refactors the `IStringMatchType` interface to make the `AreConsideredEqual` method asynchronous, changing the return type from `bool` to `Task<bool>` for .NET Standard 2.0 and `ValueTask<bool>` for .NET 8.0+. This is a breaking change that modernizes the API to support async-first patterns.

### Key changes include:
- Interface method signature updated to return asynchronous types
- All implementations updated to return wrapped task results
- Calling code updated to use async/await patterns

This PR makes the `EquivalencyExpectationBuilder` class public to enable extensibility of the aweXpect equivalency system. The refactor changes the visibility modifier from internal to public and adds proper XML documentation.

### Key changes:
- Changed `EquivalencyExpectationBuilder` from internal to public access modifier
- Added XML documentation for the newly public class
- Updated method signatures to use generic type parameters instead of object parameters

This is a maintenance PR that updates the aweXpect.Core package version from v2.21.2 to v2.22.0 in the centralized package management configuration.

- Updates aweXpect.Core dependency to version 2.22.0

This PR fixes a bug in the `It.Is` functionality when handling `null` values. The fix ensures that when comparing `null` values against expectations using `It.Is`, the comparison works correctly instead of always failing.

### Key changes:
- Modified `EquivalencyExpectationBuilder` to properly handle `null` value comparisons
- Updated test case to verify that `null` checks now succeed instead of failing
- Added new test case to verify proper error reporting when non-null checks fail on `null` values

This PR fixes error message formatting for string prefix and suffix assertions when dealing with empty strings. The changes ensure that empty strings are properly handled in error messages to avoid displaying confusing contextual information.

### Key changes:
- Updates error message logic to use `string.IsNullOrEmpty()` instead of null-only checks
- Adds conditional context display to prevent showing "Actual" context for null/empty strings
- Includes test coverage for empty string scenarios in both StartsWith and EndsWith assertions

This PR updates the aweXpect library dependencies to newer versions and re-enables previously skipped tests that were waiting for the core library update.

### Key changes:
- Updates aweXpect from 2.23.0 to 2.24.0 and aweXpect.Core from 2.22.0 to 2.22.2
- Re-enables three previously skipped unit tests that were dependent on the core library update

This PR adds new `WithoutMessage` methods for delegate assertions, providing the ability to verify that thrown exceptions do not have specific messages or message content. The feature enhances the exception assertion API by providing negative assertions for message validation.

### Key changes:
- Added `DoesNotHaveMessage` and `DoesNotHaveMessageContaining` methods for exception assertions
- Added `WithoutMessage` and `WithoutMessageContaining` methods for delegate exception assertions
- Updated error message formatting to be more consistent and include contextual information