Add MessageExpressionAuthorizationManager

[wonderfulrosemari]

Closes gh-12650

This PR promotes expression-based message authorization to a public API by
introducing MessageExpressionAuthorizationManager in the messaging module.

Changes include:

• adding MessageExpressionAuthorizationManager and unit tests
• updating the WebSocket XML parser to use the new public manager instead of
  the private inner class
• updating WebSocket migration docs to reference the built-in manager

[jzheaux]

Hi, @wonderfulrosemari! Thanks for this PR. I've left some feedback inline.

[wonderfulrosemari]

Thanks for the feedback. I removed the deprecated setter and replaced the public (expressionHandler, expression) constructor with a builder-style API using withSecurityExpressionHandler(...).expression(...), and updated the WebSocket XML parser and tests accordingly.

[jzheaux]

Thanks for the updates, @wonderfulrosemari. In preparation for merging, will you please squash your commits and change the title of your new commit to "Add MessageExpressionAuthorizationManager"?

[jzheaux]

Thanks, @wonderfulrosemari! Sorry for a miscommunication, it is still helpful to have the Closes gh-12650 in the commit message. So, like this:

Add MessageExpressionAuthorizationManager

Closes gh-12650

Signed-off-by: wonderfulrosemari <whwlsgur1419@naver.com>

This helps with future research when trying to track down why a specific change to the codebase was made. Will you please change your commit message to include the above?

[wonderfulrosemari]

Updated the commit message to include "Closes gh-12650". Thanks!