Add missing generics to API that were missed in Faces 4.0

[pnicolucci]

During MyFaces 4.0 development I opened the following issue that outlines the missing generics: https://issues.apache.org/jira/browse/MYFACES-4454

1. https://jakarta.ee/specifications/faces/4.0/apidocs/jakarta/faces/context/externalcontextwrapper#getInitParameterMap() should have a return type of Map<String,String> The ExternalContext already defines the method in the same way.

2. https://jakarta.ee/specifications/faces/4.0/apidocs/jakarta/faces/render/renderer#getConvertedValue(jakarta.faces.context.FacesContext,jakarta.faces.component.UIComponent,java.lang.Object) should take an argument of T rather than UIComponent This would align with the rest of the methods in the Renderer API.

This was missed when https://github.com/jakartaee/faces/issues/1497 was completed for Faces 4.0.