feat: added optional jsw format to json reporter

[CheadleCheadle]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions.

Description of the Change

Added an optional CLI argument ('jsw' or 'jsonStringifyWhitespace') that allows for the user to set the whitespace of the JSON reporter. If it isn't provided it defaults to the current value (2).

This change allows for more customization of the JSON output!
Closes #4889

Alternate Designs

An alternative approach might involve using a boolean CLI argument to toggle the JSON reporter and remove whitespace. However, a more precise level of customization can be achieved by using a CLI argument to control the amount of whitespace instead.

Why should this be in core?

It's a relatively simple change that simplifies the parsing of the JSON output."

Benefits

This feature would prove valuable when parsing JSON test results. For example, Splunk mandates JSON formatting with no whitespace, and having the option to generate whitespace-free JSON would enable Splunk to directly use the data without additional processing.

Possible Drawbacks

There shouldn't be any drawbacks to making this modification. It allows for further customization but is kept default if not specified.

Applicable issues

N/A

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: CheadleCheadle / name: Grant A. Cheadle (8d16512, 1b10424, a2cab8f, 092824c, e293456, ce07d18)

[JoshuaKGoldberg]

Marking as waiting for changes per #4889 (comment).

[CheadleCheadle]

I addressed the changes requested in #4889 (comment).

Instead of jsonStringifyWhiteSpace, I went with indentSize. It is not only shorter and easier to type, but clearer in what it is used for!

[coveralls]

coverage: 94.337% (-0.02%) from 94.359%
when pulling 8d16512 on CheadleCheadle:optional-reporter-format
into 3735873 on mochajs:master.