Record CHANGELOG entries from @metamask/json-rpc-{engine,middleware-stream} migrations

[MajorLift]

Explanation

Records CHANGELOG entries from @metamask/json-rpc-engine and @metamask/json-rpc-middleware-stream migrations under "Unreleased" headers for reference during the next version release.

• Records updates made to the @metamask/json-rpc-engine and @metamask/json-rpc-middleware-stream packages since its last release, and during the migration process.
• Lists these migrations as ADDED changes.
• Records version bumps of the migrated packages in downstream repos.
• Records changes made to downstream repos.

References

• Partially implements Post-migration cleanup for @metamask/json-rpc-engine #1981
• Partially implements Post-migration cleanup for @metamask/json-rpc-middleware-stream #1982

Changelog

N/A

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate

[mcmire]

I noticed a few that were potentially missing.

[mcmire]

Looks good!