LMS-967 Some refactorings needed for fixing a GUI bug for Phosphonetx

...t/web/client/application/ui/field/ChosenEntitySetter.java

.../web/client/application/ui/field/EntityChooserDialog.java

...b/client/application/ui/field/ExperimentChooserField.java

...eb/client/application/ui/field/IChosenEntityListener.java

...web/client/application/ui/field/MaterialChooserField.java

...t/web/client/application/ui/field/SampleChooserField.java

...client/application/ui/grid/AbstractSimpleBrowserGrid.java