Adding json output option to CLI ls commands

[xeniumcode]

Added json output in:

prefect variable ls
prefect artifact ls
prefect global-concurrency-limit ls
prefect deployment ls
prefect deployment schedule ls
prefect block ls
prefect block type ls

• "closes part of Add -o json output option to CLI ls commands #19483 "
• it includes unit tests that cover the changes

[codspeed-hq]

CodSpeed Performance Report

Merging #20078 will not alter performance

_{Comparing xeniumcode:issue#19483 (e9fa5cd) with main (833255d)}

Summary

✅ 2 untouched

[zzstoatzz]

hi @xeniumcode - do you mind splitting these out into smaller PRs that change one cli subgroup at a time?