Do not check for validity in Delete Duplicate Geometries alg

This isn't required, and can get in the way (Eg when the
delete duplicate geometries step is used as part of cleaning
up a dataset prior to fixing geometries)

src/analysis/processing/qgsalgorithmdeleteduplicategeometries.cpp

@@ -89,7 +89,7 @@ QVariantMap QgsDeleteDuplicateGeometriesAlgorithm::processAlgorithm( const QVari
   if ( !sink )
     throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
 
-  QgsFeatureIterator it = mSource->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() ) );
+  QgsFeatureIterator it = mSource->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() ), Qgis::ProcessingFeatureSourceFlag::SkipGeometryValidityChecks );
 
   double step = mSource->featureCount() > 0 ? 100.0 / mSource->featureCount() : 0;
   QHash< QgsFeatureId, QgsGeometry > geometries;
@@ -170,7 +170,7 @@ QVariantMap QgsDeleteDuplicateGeometriesAlgorithm::processAlgorithm( const QVari
   step = outputFeatureIds.empty() ? 1 : 100.0 / outputFeatureIds.size();
 
   const QgsFeatureRequest request = QgsFeatureRequest().setFilterFids( outputFeatureIds ).setFlags( Qgis::FeatureRequestFlag::NoGeometry );
-  it = mSource->getFeatures( request );
+  it = mSource->getFeatures( request, Qgis::ProcessingFeatureSourceFlag::SkipGeometryValidityChecks );
   current = 0;
   while ( it.nextFeature( f ) )
   {