Move domain specific code from service to Norm object

RISDEV-0000

backend/src/main/java/de/bund/digitalservice/ris/norms/application/service/AnnouncementService.java

@@ -101,18 +101,12 @@ public List<Norm> loadTargetNormsAffectedByAnnouncement(
         .orElseThrow(() -> new NormNotFoundException(query.eli().toString()));
 
     return amendingNorm
-      .getArticles()
+      .targetLawElis()
       .stream()
-      .filter(article ->
-        article.getRefersTo().isPresent() &&
-        !article.getRefersTo().get().equals("geltungszeitregel")
-      )
-      .map(article ->
+      .map(eli ->
         loadNormPort
-          .loadNorm(new LoadNormPort.Command(article.getMandatoryAffectedDocumentEli()))
-          .orElseThrow(() ->
-            new NormNotFoundException(article.getMandatoryAffectedDocumentEli().toString())
-          )
+          .loadNorm(new LoadNormPort.Command(eli))
+          .orElseThrow(() -> new NormNotFoundException(eli.toString()))
       )
       .toList();
   }

backend/src/main/java/de/bund/digitalservice/ris/norms/domain/entity/Norm.java

@@ -136,6 +136,23 @@ public List<Article> getArticles() {
       .toList();
   }
 
+  /**
+   * Returns a {@link List} of all target norms {@link ExpressionEli}s of an amending {@link Norm}.
+   *
+   * @return The list of target norm elis
+   */
+  public List<ExpressionEli> targetLawElis() {
+    return getNodesFromExpression("//body//article[not(ancestor-or-self::mod)]", document)
+      .stream()
+      .map(Article::new)
+      .filter(article ->
+        article.getRefersTo().isPresent() &&
+        !article.getRefersTo().get().equals("geltungszeitregel")
+      )
+      .map(Article::getMandatoryAffectedDocumentEli)
+      .toList();
+  }
+
   /**
    * Extracts a list of {@link Mod}s from the document.
    *
@@ -228,7 +245,7 @@ public Optional<String> getStartDateForEventRef(String eId) {
    * The temporalData node will get a new temporalGroup node as child, which will have a new
    * timeInterval node as child.
    *
-   * @param date the {@link LocalDate} for the new time boundary.
+   * @param date         the {@link LocalDate} for the new time boundary.
    * @param eventRefType the {@link EventRefType} for the new time boundary.
    * @return the newly created {@link TemporalGroup}
    */