Gracefully handle IndexedDB connection closing and reopen

Summary

Original issue reported on Slack.

When more than one tab with Studio is opened, it was taking forever to load the channel list.
Nothing was visible in My channels, Starred, and View-only, a part from the loader spinning, and a lot of DexieErrors in the console.
Once I closed the other opened tab as suggested by @kollivier, channel list appeared without issues.

Category

BUG

Usage Details

• Browser: Chrome
• Channel: -
• Topic/Content Item: -

Traceback or relevant snippet from browser console

/en/channels/#/my-channels:1 Uncaught (in promise) 
DexieError {_e: Error
    at getErrorWithStack (https://studio.learningequality.org/static/studio/channel_list-845e…, name: "InvalidStateError", message: "Failed to execute 'transaction' on 'IDBDatabase': … database connection is closing.↵ [object Object]", inner: {…}}
inner: {_e: Error at getErrorWithStack (https://studio.learningequality.org/static/studio/accounts-845ee883…, name: "InvalidStateError", message: "Failed to execute 'transaction' on 'IDBDatabase': …IDBDatabase': The database connection is closing.", inner: DOMException: Failed to execute 'transaction' on 'IDBDatabase': The database connection is closing.}
message: "Failed to execute 'transaction' on 'IDBDatabase': The database connection is closing.↵ InvalidStateError: Failed to execute 'transaction' on 'IDBDatabase': The database connection is closing.↵ [object Object]"
name: "InvalidStateError"
_e: Error at getErrorWithStack (https://studio.learningequality.org/static/studio/channel_list-845ee883853d1392960f.js:1:152009) at new DexieError (https://studio.learningequality.org/static/studio/channel_list-845ee883853d1392960f.js:1:154222) at DexiePromise.rejectionMapper (https://studio.learningequality.org/static/studio/channel_list-845ee883853d1392960f.js:1:255383) at handleRejection (https://studio.learningequality.org/static/studio/channel_list-845ee883853d1392960f.js:1:160790) at nrWrapper (https://studio.learningequality.org/en/channels/:59:26692)
stack: (...)
__proto__: DexieError

How to reproduce

Not able to reproduce it intentionally at the moment, but opening the issue to track if it reappears.

The issue names no source files, tests, or entry points. Start by tracing the DexieError and IndexedDB connection-closing path in the channel-list loading flow, then reproduce the multi-tab scenario if possible. Done means channel lists load without uncaught connection-closing errors when another Studio tab is open.