增加Excel文档加载功能，处理向量库管理createSchema方法WeaviateEmbeddingStore.builder().build();直接构建报错问题。

ruoyi-modules-api/ruoyi-knowledge-api/src/main/java/org/ruoyi/constant/FileType.java

@@ -7,6 +7,8 @@ public class FileType {
     public static final String DOC = "doc";
     public static final String DOCX = "docx";
     public static final String PDF = "pdf";
+    public static final String XLS = "xls";
+    public static final String XLSX = "xlsx";
 
     public static final String LOG = "log";
     public static final String XML = "xml";
@@ -88,4 +90,13 @@ public class FileType {
         }
     }
 
+    public static boolean isExcel(String type){
+        if (type.equalsIgnoreCase(XLS) || type.equalsIgnoreCase(XLSX)){
+            return true;
+        }
+        else {
+            return false;
+        }
+    }
+
 }