DATACMNS-479 - Make sure Map types are not added to the mapping context.

Changed the algorithm for nested PersistentEntity detection to only use PersistentProperty.getPersistentEntityTypes(…) and make sure we return unwrap Maps and Collections inside the method correctly.

src/main/java/org/springframework/data/mapping/context/AbstractMappingContext.java

@@ -466,10 +466,6 @@ public abstract class AbstractMappingContext<E extends MutablePersistentEntity<?
 				return;
 			}
 
-			if (!property.isEntity()) {
-				return;
-			}
-
 			for (TypeInformation<?> candidate : property.getPersistentEntityType()) {
 				addPersistentEntity(candidate);
 			}

src/main/java/org/springframework/data/mapping/model/AbstractPersistentProperty.java

@@ -126,7 +126,7 @@ public abstract class AbstractPersistentProperty<P extends PersistentProperty<P>
 			if (nestedType != null) {
 				result.add(nestedType);
 			}
-		} else {
+		} else if (isEntity()) {
 			result.add(type);
 		}