[backport#16044] qt: fix opening bitcoin.conf via Preferences on macOS
Summary:
6e6494b3fb345848025494cb7a79c5bf8f35e417 qt: fix opening bitcoin.conf via Preferences on macOS; see #15409 (shannon1916)
Pull request description:
Fix #15409. The QT wallet fail to open the configuration file on Mac, when these is no default application for `*.conf` files. Here is a feasible way to solve this bug. When `QDesktopServices::openUrl` fails to open `file:///path/bitcoin.conf` with its default application, use `QProcess::startDetached` to run `open -t /path/bitcoin.conf` command instead, so as to open the configuration file with system's default text editor.
Backport of Core PR16044
Test Plan:
ninja all check check-functional
I don't have a mac to test this unfortunately
Reviewers: #bitcoin_abc, deadalnix
Reviewed By: #bitcoin_abc, deadalnix
Differential Revision: https://reviews.bitcoinabc.org/D8665