Maven properties that are flagged read-only for command-line binding lead to warnings with Maven 4

[snicoll]

See #43596

Some of our Mojos have a POJO structure for some of the parameters. For instance, the spring-boot:build-image goal as an <image> property that contains sub-properties such as name and the like.

Maven does not allow to bind a property of a POJO from the command line. To workaround this issue, the only way we found was to declare the parameter again, but flag it read-only so that it doesn't show up in auto-completion.

Maven 4 now makes use of that read-only flag and outputs a warning. We need to figure out what to do to preserve the current behavior.