Fix compilation issues around Prose handling

We will have to re-implement Prose manipulation later on. Project will be better
served if we just remove the current implementation and re-implement once the
project compiles with the latest oscal.

impl/implementation.go

@@ -379,8 +379,6 @@ func getSubControlIDFromParam(paramID string) string {
 
 func getGuidanceFromPart(part *catalog.Prose) []string {
 	var guidance []string
-	for _, p := range part.P {
-		guidance = append(guidance, p.Raw)
-	}
+	guidance = append(guidance, part.Raw)
 	return guidance
 }

types/oscal/catalog/helpers.go

@@ -12,9 +12,7 @@ func NewPart(id, title, narrative string) Part {
 	return Part{
 		Id:    id,
 		Title: Title(title),
-		Prose: &Prose{
-			P: []P{P{Raw: narrative}},
-		},
+		Prose: &Prose{Raw: narrative},
 	}
 }
 

types/oscal/catalog/import.go

@@ -0,0 +1,7 @@
+package catalog
+
+import (
+	"github.com/docker/oscalkit/types/oscal/nominal_catalog"
+)
+
+type Prose = nominal_catalog.Prose