workbox-background-sync doesn't sync when back online

[megganeturner]

Description

When using workbox-background-sync, requests are successfully added to the queue, but never replayed when a user comes back online.

Steps to Reproduce

1. Go to this demo & follow the instructions to make a request offline
2. When offline, the network request is populated in the queue in Application > Storage > IndexedDB > workbox-background-sync > requests > queueName

3. When coming back online, the queued network requests are not replayed, and they just sit in the queue indefinitely
4. You can manually force the queue to sync in the dev tools, but it just doesn't happen automatically

Actual result:

The requests stay in the queue indefinitely, even after reconnecting to internet

Expected result:

The requests should replay upon reconnecting to internet

Reproduces how often:

Easily reproduced - this feature has not worked for at least a few weeks

Brave version (brave://version info)

Brave: 1.43.93 Chromium: 105.0.5195.127 (Official Build) (x86_64)
Revision: 912488396852bf658ab32465980c0b93a3c27a83-refs/branch-heads/5195@{#1109}
OS: macOS Version 12.4 (Build 21F79)

Version/Channel Information:

• Can you reproduce this issue with the current release?
  • Yes
• Can you reproduce this issue with the beta channel?
  • Yes
• Can you reproduce this issue with the nightly channel?
  • Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
  • No
• Does the issue resolve itself when disabling Brave Rewards?
  • No
• Is the issue reproducible on the latest version of Chrome?
  • No, the feature/demo works as expected on Chrome and the requests are replayed as soon as the user comes back online

Miscellaneous Information:

N/A