Spring Remove unnecessary else statements in AbstractMediaTypeExpression

In this PR, I've refactored the compareTo method in the AbstractMediaTypeExpression class. The main change involves simplifying the conditional structure by removing the unnecessary else statements. This enhances readability and align the code style with the equals method

Changes Made: - Removed unnecessary else statements in the compareTo method. - Retained the original logic and functionality.

Comment From: snicoll

Thanks for the PR but things like this are largely subjective and we don't really accept PRs like this. In any case, I think that the current code reads better anyway.