KOP-2964 fixed findings in merge requests

pom.xml

@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>de.ozgcloud.common</groupId>
 		<artifactId>ozgcloud-common-parent</artifactId>
-		<version>4.9.0-SNAPSHOT</version>
+		<version>4.9.0</version>
 	</parent>
 
 	<groupId>de.ozgcloud.osiv2</groupId>
@@ -48,21 +48,7 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-oauth2-client</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>jakarta.servlet</groupId>
-			<artifactId>jakarta.servlet-api</artifactId>
-		</dependency>
-		<dependency>
-			<groupId>jakarta.json.bind</groupId>
-			<artifactId>jakarta.json.bind-api</artifactId>
-			<version>3.0.1</version>
-		</dependency>
-		<dependency>
-			<groupId>org.eclipse</groupId>
-			<artifactId>yasson</artifactId>
-			<version>3.0.4</version>
-			<scope>test</scope>
-		</dependency>
+
 
 		<dependency>
 			<groupId>org.mapstruct</groupId>

src/main/java/de/ozgcloud/nachrichten/postfach/osiv2/config/ApiClientConfiguration.java

@@ -36,7 +36,6 @@ public class ApiClientConfiguration {
 
 	private final OsiPostfachProperties.ApiConfiguration apiConfiguration;
 	private final OsiPostfachProperties.ProxyConfiguration proxyConfiguration;
-	private static final String RESOURCE_HEADER = "resource";
 
 	@Bean
 	MessageExchangeApi messageExchangeApi(ApiClient apiClient) {

src/main/java/de/ozgcloud/nachrichten/postfach/osiv2/config/OsiPostfachProperties.java

@@ -44,9 +44,7 @@ public class OsiPostfachProperties {
 
 		private boolean enabled;
 
-		@Nullable
 		private String host;
-		@Nullable
 		private Integer port;
 
 		@Nullable