[backport#13339] wallet: Replace %w by wallet name in -walletnotify script

Summary:
test: Check wallet name in -walletnotify script (João Barbosa)
wallet: Replace %w by wallet name in -walletnotify script (João Barbosa)

Pull request description:

Fixes #13237.

https://github.com/bitcoin/bitcoin/pull/13339/files

Backport of Core PR13339

Test Plan:

ninja all check check-functional

Reviewers: #bitcoin_abc, PiRK

Reviewed By: PiRK

Differential Revision: https://reviews.bitcoinabc.org/D8129