Perf: Reduce memory overhead in transitive dependency

[toddtreece]

What is this feature?

Reduces go_memstats_heap_inuse_bytes from ~65MB to ~45MB on a mostly idle (except profiling) Grafana instance, by switching to lazy initialization of global variables in go-json.

Related PR: goccy/go-json#490

Why do we need this feature?

go-json is a dependency of Apache Arrow v13. Grafana does not currently use Arrow's JSON encoding/decoding, but Arrow's import of go-json is adding additional memory overhead due to how some global variables are initialized.

This is pretty easy to spot when looking at Pyroscope flamegraphs:

Who is this feature for?

[Add information on what kind of user the feature is for.]

Which issue(s) does this PR fix?:

Fixes #

Special notes for your reviewer:

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.

[toddtreece]

/deploy-to-hg

[ephemeral-instances-bot]

• Preparing your instance. A comment containing your instance's url will be added to this PR when the instance is ready.
• Your instance will be ready in ~10 minutes.
• Check the GitHub actions tab to follow the workflow progress
• Slack channel: #proj-ephemeral-hg-instances
• Building instance with toddtreece/arrow-json oss branch and main enterprise branch. How to choose a branch

[ephemeral-instances-bot]

• Your instance can be accessed at: https://ephemeral1511182178651toddtre.grafana-dev.net
• The instance is not using the CDN assets.
• How to access / How to update instance config / How to build a specific branch

[github-actions]

This pull request has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 2 weeks if no further activity occurs. Please feel free to give a status update or ping for review. Thank you for your contributions!

[github-actions]

This pull request has been automatically closed because it has not had any further activity in the last 2 weeks. Thank you for your contributions!