[fix](disk migrate) migrate ignore not exists tablet (#26779)

fe/fe-core/src/main/java/org/apache/doris/master/ReportHandler.java

@@ -979,6 +979,9 @@ public class ReportHandler extends Daemon {
             for (int i = 0; i < tabletMetaList.size(); i++) {
                 long tabletId = tabletIds.get(i);
                 TabletMeta tabletMeta = tabletMetaList.get(i);
+                if (tabletMeta == TabletInvertedIndex.NOT_EXIST_TABLET_META) {
+                    continue;
+                }
                 // always get old schema hash(as effective one)
                 int effectiveSchemaHash = tabletMeta.getOldSchemaHash();
                 StorageMediaMigrationTask task = new StorageMediaMigrationTask(backendId, tabletId,