Change Qt 5/6 compat for QML

James Turnerrequested to merge
bugfix/qt-6-compat into release/2024.1

Instead of using a selector, which is causing load failures with Qt 6.11, switch to using a custom name for the RegularExpressionValidator. The underlying C++ type is availabl back to 5.1, so expose it as FGRegExpValidator everywhere.

This avoids the need to customize Settings.qml

Issue-Id: #3441 (closed)

Merge request reports