Fixes firestore replication of multiple document with the same serverTimestamp

[djoume]

This PR contains:

• A BUGFIX

Describe the problem you have without this PR

I noticed some documents where missing when replicating from firestore. I traced down the issue to a bug in the sameTimeQuery in the firestore plugin where we're querying for a document field instead of querying for a document id.

I'm not sure how to test a change to this library on my project, could you advise on how to do so? I don't think I can use npm link because of the build steps required.

[pubkey]

To test this, clone the rxdb project into your node_modules/rxdb. Then run npm run build inside of it.

[djoume]

I finally found what was preventing me for testing changes to rxdb, I had forgot to exclude rxdb from vite's optimizeDeps config.

I have been able to confirm that with this change all documents are being fetched, let me know if there is anything else I can do to help get this bugfix merged.

[pubkey]

Thank you, merged.