Remove storage disconnected warning continue study button

[jaykim1213]

Does this PR close any open issues?

Towards #1182

Give a longer description of what this PR addresses and why it's needed

This PR updates the storage disconnected modal to prevent participants from continuing a study when cloud storage is unavailable.

• Makes the storage disconnected warning non-dismissible
• Changes the modal button from "Continue Study" to "Reconnect"
• In production, prevents silent fallback to localStorage when Firebase or Supabase is configured
• Adds a modal when falling back to localStorage in non-production mode

Storage disconnected warning

• Cloud storage is configured (firebase or supabase)
• The app is running in production mode
• The app cannot connect to the configured cloud storage

localStorage fallback warning

• Cloud storage is configured (firebase or supabase)
• The app fails to connect to cloud storage
• The app is running in non-production mode and falls back to localStorage

TODOs

• Refactor
• Add auto-reconnect
• Test (adblockers + disconnects)

[github-actions]

A preview of 764eba5 is uploaded and can be seen here:

✨ https://revisit.dev/study/PR1287 ✨

Changes may take a few minutes to propagate.

[JackWilb]

The new blocking modal does not observe failures from the actual debounced participant-data upload, so this needs to be corrected before merge.

[JackWilb]

What messages are not storage engine alerts?
We probably don't want to await in goToNextStep

[jaykim1213]

@JackWilb

What messages are not storage engine alerts?

The alerts that can still be closed are things like "Problem loading the study", "Using localStorage fallback", "Failed to Advance", and "Prohibited".
The only alerts we block are the storage ones where continuing could lose data: "Failed to connect to the storage engine" and "Failed to Save Response"

We probably don't want to await in goToNextStep

Updated this so goToNextStep does not wait for the upload anymore. If the delayed queued upload fails later, we now catch that through the storage engine listener and show the modal from there.