If true, users may control whether the version check is enabled
or disabled through the QGIS settings dialog. (The default
check behavior is determined by the existing 'checkVersion' setting).
If false, no version checking will be performed AND users will NOT
have an option to enable this check in the settings dialog.
This setting is intended for use in enterprise installs where QGIS version
management is handled centrally.
- Switch to flags instead of boolean argument
- Move logic for layer validity to canRunUsingLayer
- Add unit test
Also remove settings flag to hide duplicate features action
Since there's a number of serious outstanding issues with these
tools, hide them by default and show them only if a QgsSettings
flag is set ("tools\showDuplicateFeatureActions").
This allows the tools to be reworked for 3.2, while still
making them accessible for users who require their functionality.