STYLE: use dictionary checking methods in runTimePostProcessing

src/runTimePostProcessing/fieldVisualisationBase.C

src/runTimePostProcessing/functionObjectBase.C

src/runTimePostProcessing/geometryBase.C

src/runTimePostProcessing/geometryPatches.C

src/runTimePostProcessing/runTimePostProcessing.C

src/runTimePostProcessing/scene.C

src/runTimePostProcessing/surface.C

src/runTimePostProcessing/text.C