WIP: assets/js: add polyfill for Object.hasOwn() to make comments work

[goapunk]

assets/js: add polyfill for Object.hasOwn() to make comments work on older browsers.

Describe your changes Brought over from a+ -> https://github.com/liqd/adhocracy-plus/pull/2742

Testing: Test on older browsers (e.g. safari 14) with any module which has comments

Tasks

• [ ] PR name contains story or task reference
• [x] Steps to recreate and test the changes
• [ ] Documentation (docs and inline)
• [ ] Tests (including n+1 and django_assert_num_queries where applicable)
• [x] Changelog

[hom3mad3]

cc @sblindow do we have a list of supported browsers bzw. devices?

[goapunk]

closing as we don't need to support safari 14 anymore.