fix: FIREBASE always assumes prolific

This makes it hard to test because the prolificID is `undefined`. Looking at the Firestore there are a >800 trials under the `undefined` participant, which are all the tests, but since no date is saved for a trial is impossible to know what's the lates test.

Instead of assuming that is not using MTURK, then we must be using prolific as done in [here](https://github.com/lnccbrown/task-effort/blob/43bb3f74f680ae0b3ec5f3550a91cd5adc2e3d5b/src/config/main.js#L78), one could further check that if there is a prolificId available as done in more recent honeycomb [here](https://github.com/brown-ccv/honeycomb/blob/729770d9866cc6e82cd05e06ae630a5d67215756/src/config/main.js#L41). That way, where there is not a prolificId, maybe one could still be asked for an ID to enter

Start in src/config/main.js and compare the participant-ID handling with the task-effort and honeycomb implementations linked in the issue. Check the Firebase/Firestore path for trials without a prolificId, then verify that those participants are not automatically treated as Prolific and can still be prompted for an ID.

Written by the indexing model from the issue text.