Add unit tests for ResponseValidator with Mockito integration

Introduced `ResponseValidatorTest` to comprehensively test the `ResponseValidator` class. Enhanced the project dependencies by updating JUnit to 5.12.2 and integrating Mockito with `mockito-junit-jupiter` 5.17.0 for mocking support. Clarified Javadoc for handling `RecordMultipleResponse` cases in `ResponseValidator`.

pom.xml

@@ -37,7 +37,8 @@
         <lombok.version>1.18.36</lombok.version>
         <slf4j.version>2.0.17</slf4j.version>
         <logback-classic.version>1.5.18</logback-classic.version>
-        <junit5.version>5.11.4</junit5.version>
+        <junit5.version>5.12.2</junit5.version>
+        <mockito-junit5.version>5.17.0</mockito-junit5.version>
 
         <!-- sonarqube -->
         <sonar.organization>thischwa</sonar.organization>
@@ -117,6 +118,12 @@
             <version>${junit5.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <version>${mockito-junit5.version}</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>