fix: improve test to restore property before test

Author: iaorekhov-1980

fe/fe-core/src/test/java/org/apache/doris/mysql/authenticate/ldap/LdapAuthenticatorTest.java

@@ -29,6 +29,7 @@
 import mockit.Expectations;
 import mockit.Mocked;
 import org.junit.After;
+import org.junit.Before;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -168,4 +169,9 @@ public void testEmptyPassword() throws IOException {
     public void tearDown() {
         LdapConfig.ldap_allow_empty_pass = true; // restoring default value for other tests
     }
+
+    @Before
+    public void setUp() {
+        LdapConfig.ldap_allow_empty_pass = true; //restoring default value for other tests
+    }
 }