Merge #13773: wallet: Fix accidental use of the comma operator

Summary:
aecd615ad7 wallet: Fix accidental use of the comma operator (practicalswift)

Pull request description:

Fix accidental use of the comma operator.

Tree-SHA512: 035bf497343996c67a2fe25f367d1a416811b518cb9c7a18ce92355627871614e40db699e869881f941bc51e47fb94022f5ae13e7f01462ef35249b2dd3647a0

Backport of Core PR13773
https://github.com/bitcoin/bitcoin/pull/13773/

Test Plan:

make check

Reviewers: deadalnix, Fabien, jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Reviewed By: jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D4764