ProjectExplorer: Remove IDeviceFactory::setCanCreate

That's implicit now by using setCreator()

The Android case looks odd as this is (and was) effectively static
information at startup. This will be addressed in a follow-up patch,
for now keep it functionally equivalent.

Change-Id: I4e6082f88dcd21379186340189acb581caef172a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/remotelinux/filesystemaccess_test.cpp

@@ -52,7 +52,6 @@ TestLinuxDeviceFactory::TestLinuxDeviceFactory()
     setDisplayName("Generic Linux Device");
     setIcon(QIcon());
     setConstructionFunction(&LinuxDevice::create);
-    setCanCreate(true);
     setCreator([] {
         LinuxDevice::Ptr newDev = LinuxDevice::create();
         qDebug() << "device : " << newDev->type();