#13126 RiaLogging: Extract errorInMessageBox to RiuMessageDialog

Move the QMessageBox-displaying helper out of the logging utility into a
dedicated UI class. RiaLogging.h no longer pulls QMessageBox/QWidget into
the ~270 files that include it. Behavior is preserved: showError displays
the dialog when running interactively (and not under regression tests),
then forwards the text to RiaLogging::error.

ApplicationLibCode/Commands/RicImportObservedFmuDataFeature.cpp

@@ -21,6 +21,7 @@
 #include "RiaApplication.h"
 #include "RiaGuiApplication.h"
 #include "RiaLogging.h"
+#include "RiuMessageDialog.h"
 
 #include "RicImportFormationNamesFeature.h"
 
@@ -62,7 +63,7 @@ void RicImportObservedFmuDataFeature::selectObservedDataPathInDialog()
                               .arg( RifReaderFmuRft::wellPathFileName() )
                               .arg( directory );
 
-        RiaLogging::errorInMessageBox( nullptr, "Import of Observed FMU Data", message );
+        RiuMessageDialog::showError( nullptr, "Import of Observed FMU Data", message );
 
         return;
     }