Refactor AgainstExpression to Expression for Clarity and Consistency

[SimonNyvall]

Fix: Update AgainstExpression to Expression

Summary: This PR addresses issue #309. The changes include renaming AgainstExpression to Expression, marking the former as obsolete, and ensuring that the new method clearly indicates that the expression should describe the INVALID state.

Changes Made:

• Deprecated AgainstExpression method and marked it as [Obsolete].
• Renamed the GuardAgainstExpressionExtenssion to GuardAgainstExpressionExtenssionDeprecated
• Created AgainstExpressionExtenssion with CallerArgumentExpression
• Incorporated CallerArgumentExpression attribute for better clarity in exception messages.
• Updated documentation and comments to clearly indicate that the expression parameter should describe the invalid case, and when it evaluates to true, it implies the input is in an invalid state.

Testing:

• Added unit tests for the new Expression method covering various scenarios.
• Renamed the GuardAgainstExpression to GuardAgainstExpressionDeprecated
• Manually tested to ensure backward compatibility.

Checklist:

• Deprecated AgainstExpression method.
• Implemented new Expression method.
• Updated unit tests.
• Updated documentation.

@ardalis Please review the changes and provide your insights.

[ardalis]

Your comments say the expression will throw if the func evaluates to true but your actual code and tests say that it should throw when the func is false. Keep the comments and change the code to match.

[SimonNyvall]

Thank you for the feedback! Made two more commits addressing the issues.

[ardalis]

Thanks, I'll get this out soon!