DEVDOCS-6034 [update]: Settings API, update docs for channel overrides

[bc-andreadao]

DEVDOCS-6034

This PR addresses issue 388

Relevant slack conversation

What changed?

Get Locale Settings & Update Locale Settings endpoint:

• add channel_id query parameter
• Response body: if there are no channel overrides, data will be null

Update Locale Settings endpoint:

• Document how to remove overrides (set each field to null)

Release notes draft

N / A

Anything else?

@bigcommerce/team-multi-storefront

[funivan]

We need to talk with product first.

Blocking this PR because of this change: - $ref: '#/components/parameters/ChannelIdParam'

[bc-andreadao]

Thanks @funivan, keep me in the loop on the conversation

[kristinapototska]

@bc-andreadao is there someone requesting this change to documentation?
I'm asking, because we have intentionally removed this from documentation as we are not planning to make this change public and instead we will be release a separate API endpoint to manage locales per channel.

[bc-andreadao]

@kristinapototska Yes, the PR was created to address #388 from an external developer. However, I can close out the PR and notify them that we're planning to release a separate API endpoint in the future, if that's what you'd prefer.