chore(backend): replace @Configuration with @TestConfiguration in test classes

- Adjusted annotations in `PingControllerIntegrationTest` and `PingControllerTest` to improve test context setup.

backend/services/ping/ping-service/src/test/kotlin/at/mocode/ping/service/PingControllerIntegrationTest.kt

@@ -12,8 +12,8 @@ import org.junit.jupiter.api.Test
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.beans.factory.annotation.Qualifier
 import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest
+import org.springframework.boot.test.context.TestConfiguration
 import org.springframework.context.annotation.Bean
-import org.springframework.context.annotation.Configuration
 import org.springframework.context.annotation.Import
 import org.springframework.context.annotation.Primary
 import org.springframework.test.context.ActiveProfiles
@@ -42,7 +42,7 @@ class PingControllerIntegrationTest {
     @Qualifier("pingUseCaseIntegrationMock")
     private lateinit var pingUseCase: PingUseCase
 
-    @Configuration
+    @TestConfiguration
     class PingControllerIntegrationTestConfig {
         @Bean("pingUseCaseIntegrationMock")
         @Primary

backend/services/ping/ping-service/src/test/kotlin/at/mocode/ping/service/PingControllerTest.kt

@@ -16,8 +16,8 @@ import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.beans.factory.annotation.Qualifier
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
 import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest
+import org.springframework.boot.test.context.TestConfiguration
 import org.springframework.context.annotation.Bean
-import org.springframework.context.annotation.Configuration
 import org.springframework.context.annotation.Import
 import org.springframework.context.annotation.Primary
 import org.springframework.test.context.ActiveProfiles
@@ -54,7 +54,7 @@ class PingControllerTest {
     @Autowired
     private lateinit var objectMapper: ObjectMapper
 
-    @Configuration
+    @TestConfiguration
     class PingControllerTestConfig {
         @Bean("pingUseCaseMock")
         @Primary