✨ [PANA-5359] - Support Change records in the developer extension

[sethfowler-datadog]

Motivation

The new encoding for DOM mutations being added in #4060 involves a new record type, BrowserChangeRecord. I've added support for BrowserChangeRecords to the replay sandbox. However, they don't yet work in the developer extension, because the replay sandbox version it's using is too old.

Changes

This PR updates the developer extension to use the latest version of the replay sandbox, bringing in support for playing back sessions that include BrowserChangeRecords.

Test instructions

1. Check out this PR's branch.
2. Build the extension locally and load it using Chrome's extension manager in the usual way.
3. Go to staging. (It currently has the new serialization code; hopefully this doesn't get reset on Monday!)
4. Use the developer extension to enable the use_change_records experimental feature.
5. Confirm that Live Replay in the extension still works.

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.

[BeltranBulbarellaDD]

LGTM, works as intended!