fix: samples/client/echo_api/java/feign-gson/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-COMFASTERXMLJACKSONCORE-10500754
- https://snyk.io/vuln/SNYK-JAVA-COMFASTERXMLJACKSONCORE-7569538

Author: snyk-bot

samples/client/echo_api/java/feign-gson/pom.xml

@@ -303,7 +303,7 @@
         <feign-version>13.2.1</feign-version>
         <feign-form-version>3.8.0</feign-form-version>
         <gson-version>2.10.1</gson-version>
-        <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
+        <jackson-databind-nullable-version>0.2.7</jackson-databind-nullable-version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
         <beanvalidation-version>2.0.2</beanvalidation-version>
         <junit-version>5.10.0</junit-version>