fix AbstractEntityRepositoryService tests

Test fails because AtomicInteger i starts from 0 for each test.
This throws uniq index violation on security name

src/test/java/ru/investbook/api/AbstractEntityRepositoryServiceTest.java

@@ -25,7 +25,6 @@
 import org.springframework.boot.test.context.SpringBootTest;
 
 import java.time.Duration;
-import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 
@@ -35,10 +34,9 @@
 @SpringBootTest(properties = "spring.datasource.url=jdbc:h2:mem:testdb;mode=mysql;non_keywords=value")
 class AbstractEntityRepositoryServiceTest {
 
+    static final AtomicInteger i = new AtomicInteger();
     @Autowired
-    private SecurityRestController service;
-    private final Random random = new Random();
-    private final AtomicInteger i = new AtomicInteger();
+    SecurityRestController service;
 
     @Test
     void insert() {