[kotlin-sever][jaxrs-spec] Fix default value, add nullable support

[wing328]

• Fix default value
• add nullable support
• add tests

a follow-up PR to #14413

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CC @jimschubert (2017/09) ❤️, @dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10) @4brunu (2019/11) @yutaka0m (2020/03) @stefankoppier (2022/06)

[wing328]

Just merged this as I've other PRs for kotlin generators. If anyone has any question/feedback on this PR, happy to address it later.

[stephan-strate]

The removal of the " around the default value seems to cause problems with values other than string. As far as I know, the default value does only support string values. So for example integers or enums need to be passed as string as well. With this change, it is not compilable anymore.

The pull requests states "Fix default value". Can you elaborate on this?

[wing328]

@stephan-strate thanks for upgrading to v7.0.0 and reporting the issue. I wonder if you can open an issue to track this regression and provide a minimal spec to reproduce the problem.

I'll try to look into it later this week.

[stephan-strate]

Created issue #16455, will provide pull request