Revert "Default AuthenticatedPrincipal.getName implementation"

This reverts commit 25f8bec.

oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/DefaultOAuth2AuthenticatedPrincipal.java

@@ -64,7 +64,7 @@ public DefaultOAuth2AuthenticatedPrincipal(String name, Map<String, Object> attr
 		this.attributes = Collections.unmodifiableMap(attributes);
 		this.authorities = (authorities != null) ? Collections.unmodifiableCollection(authorities)
 				: AuthorityUtils.NO_AUTHORITIES;
-		this.name = (name != null) ? name : (String) this.attributes.get("sub");
+		this.name = (name != null) ? name : (String) this.attributes.get(this.getNameAttributeKey());
 	}
 
 	/**

oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/OAuth2AuthenticatedPrincipal.java

@@ -64,9 +64,4 @@ default <A> A getAttribute(String name) {
 	 */
 	String getNameAttributeKey();
 
-	@Override
-	default String getName() {
-		return getAttribute(getNameAttributeKey()).toString();
-	}
-
 }

oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/user/DefaultOAuth2User.java

@@ -79,6 +79,11 @@ public DefaultOAuth2User(Collection<? extends GrantedAuthority> authorities, Map
 		this.nameAttributeKey = nameAttributeKey;
 	}
 
+	@Override
+	public String getName() {
+		return this.getAttribute(this.nameAttributeKey).toString();
+	}
+
 	@Override
 	public Collection<? extends GrantedAuthority> getAuthorities() {
 		return this.authorities;