Bump com.fasterxml.jackson.core:jackson-core in /test-clients

Bumps [com.fasterxml.jackson.core:jackson-core](https://github.com/FasterXML/jackson-core) from 2.19.2 to 2.21.1.
- [Commits](FasterXML/jackson-core@jackson-core-2.19.2...jackson-core-2.21.1)

---
updated-dependencies:
- dependency-name: com.fasterxml.jackson.core:jackson-core
  dependency-version: 2.21.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

test-clients/pom.xml

@@ -38,7 +38,7 @@
         <!-- OpenAPI Generator with "restclient" -->
         <!-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -->
         <spring-web-version>6.2.13</spring-web-version>
-        <jackson-version>2.19.2</jackson-version>
+        <jackson-version>2.21.1</jackson-version>
         <jackson-databind-version>2.19.2</jackson-databind-version>
         <jakarta-annotation-version>2.1.1</jakarta-annotation-version>