[BugFix]fix npe issue for external table (#51767)

Signed-off-by: zombee0 <[email protected]>
(cherry picked from commit 067508d)

fe/fe-core/src/main/java/com/starrocks/sql/analyzer/AnalyzerUtils.java

@@ -940,6 +940,7 @@ private Table copyTable(Table originalTable) {
  }
  }
 
+ // The conception is not very clear, be careful when use it.
  private static class ExternalTableCollector extends TableCollector {
  List<Table> tables;
  Predicate<Table> predicate;
@@ -952,9 +953,7 @@ public ExternalTableCollector(List<Table> tables, Predicate<Table> filter) {
  @Override
  public Void visitTable(TableRelation node, Void context) {
  Table table = node.getTable();
- boolean internal = CatalogMgr.isInternalCatalog(table.getCatalogName())
- || table.isNativeTableOrMaterializedView()
- || table.isOlapView();
+ boolean internal = table.isNativeTableOrMaterializedView() || table.isOlapView();
  if (!internal && predicate.test(table)) {
  tables.add(table);
  }