Ensure that sensible Jackson defaults are applied at startup

[robbavey]

Logstash 8.12.0 added properties with increased defaults to config/jvm.options, to ensure that Logstash would continue to run correctly after a change to Jackson imposed a number of read constraints (Maximum Number value length, Maximum String value length, and Maximum Nesting depth).

While this change would be applied for users using a fresh version of config/jvm.options, users who have previously made changes to config/jvm.options, or users who are managing their own config/jvm.options would not get these changes after an upgrade, as the original file would be left in tact.

This can be problematic, as the default maximum allowed size by Jackson may be too small, which may result in issues such as #16683, when reading events.

We should ensure that a sensible default, as provided in the original additions to config/jvm.options, is applied at runtime if no setting is included. This is something we already do for the Netty maxOrder value.