Faces 4.0: remove deprecated "current component" constants from UIComponent

[BalusC]

Following constants must be removed from UIComponent.

    public static final String CURRENT_COMPONENT = "jakarta.faces.component.CURRENT_COMPONENT";

    public static final String CURRENT_COMPOSITE_COMPONENT = "jakarta.faces.component.CURRENT_COMPOSITE_COMPONENT";

    public static final String HONOR_CURRENT_COMPONENT_ATTRIBUTES_PARAM_NAME = "jakarta.faces.HONOR_CURRENT_COMPONENT_ATTRIBUTES";

They were basically superseded by UIComponent#getCurrentComponent() and getCurrentCompositeComponent() methods.

History: eclipse-ee4j/mojarra#1627

The guarantee that the current and current composite components are
available through FacesContext.getAttributes() doesn't seem right for
several reasons:

1. It isn't useful. The static methods
   UIComponent.getCurrentComponent() and
   UIComponent.getCurrentCompositeComponent() are more convenient and typesafe.
2. It is dangerous. If the values of these attributes is set, the
   current stack will be messed up
3. When we aren't using the particular space-inefficient implementation
   the JSF RI currently uses, maintaining these attributes just in case a
   developer tries to request them is a waste

[BalusC]

TODO: update spec to undocument jakarta.faces.HONOR_CURRENT_COMPONENT_ATTRIBUTES context param (if any at all).

Update: cannot find it, so no changes over there.

[tandraschko]

+1
will be my next task in MF

[tandraschko]

COmmited now

[arjantijms]

COmmited now

\o/