wallet: Remove path checking code from bitcoin-wallet tool

Summary:
This commit does not change behavior except for error messages which now
include more complete information.

This concludes backport of core#19619 [8/8]
https://github.com/bitcoin/bitcoin/pull/19619/commits/7bf6dfbb484adfda3b8df26ee3e2ebda239dd263

Depends on D10230

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10231