[BE] Update tests for confluent platform 7+ (#3038)

Co-authored-by: iliax <ikuramshin@provectus.com>

kafka-ui-api/src/test/java/com/provectus/kafka/ui/KafkaConnectServiceTests.java

@@ -1,6 +1,7 @@
 package com.provectus.kafka.ui;
 
 import static java.util.function.Predicate.not;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.provectus.kafka.ui.model.ConnectorDTO;
@@ -335,7 +336,7 @@ public class KafkaConnectServiceTests extends AbstractIntegrationTest {
         .exchange()
         .expectStatus().isOk()
         .expectBodyList(ConnectorPluginDTO.class)
-        .value(plugins -> assertEquals(14, plugins.size()));
+        .value(plugins -> assertThat(plugins.size()).isGreaterThan(0));
   }
 
   @Test

kafka-ui-api/src/test/java/com/provectus/kafka/ui/container/KafkaConnectContainer.java

@@ -39,7 +39,10 @@ public class KafkaConnectContainer extends GenericContainer<KafkaConnectContaine
     withEnv("CONNECT_INTERNAL_VALUE_CONVERTER", "org.apache.kafka.connect.json.JsonConverter");
     withEnv("CONNECT_REST_ADVERTISED_HOST_NAME", "kafka-connect");
     withEnv("CONNECT_REST_PORT", String.valueOf(CONNECT_PORT));
-    withEnv("CONNECT_PLUGIN_PATH", "/usr/share/java,/usr/share/confluent-hub-components");
+    withEnv("CONNECT_PLUGIN_PATH",
+        "/usr/share/java,/usr/share/confluent-hub-components,"
+            // adding additional paths to find FileStreamSinkConnector
+            + "/usr/local/share/kafka/plugins,/usr/share/filestream-connectors");
     return self();
   }