No need to check for duplicate fileids in all dbenvs

Summary:
Since we have .walletlock in each directory, we don't need the duplicate
fileid checks across all dbenvs as it shouldn't be possible anyways.

This is a backport of core#19335 [4/5]
https://github.com/bitcoin/bitcoin/pull/19335/commits/00f0041351bcd6ddbab110df1189f79ce011e192

Depends on D10036

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D10037