Spring Simplify Conventions.attributeNameToPropertyName()

I propose refactored code to simplify code and improve accuracy of Conventions.attributeNameToPropertyName() method.

Comment From: rstoyanchev

Thanks for the PR but while the proposed solution is fewer in lines, it is less optimal in terms of Object allocation and performance. As Conventions can be used in hot paths such as serving requests, so we'll keep the current solution.

Comment From: YooInKeun

Thank you for your kind review👍