chore(deps): Bump com.openai:openai-java from 4.18.0 to 4.21.0 (#21486)

Bumps [com.openai:openai-java](https://github.com/openai/openai-java) from 4.18.0 to 4.21.0.
- [Release notes](https://github.com/openai/openai-java/releases)
- [Changelog](https://github.com/openai/openai-java/blob/main/CHANGELOG.md)
- [Commits](openai/openai-java@v4.18.0...v4.21.0)

---
updated-dependencies:
- dependency-name: com.openai:openai-java
  dependency-version: 4.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

parent/pom.xml

@@ -427,7 +427,7 @@
         <olingo2-version>2.0.13</olingo2-version>
         <olingo4-version>5.0.0</olingo4-version>
         <ognl-version>3.4.10</ognl-version>
-        <openai-java-version>4.18.0</openai-java-version>
+        <openai-java-version>4.21.0</openai-java-version>
         <openapi-generator-version>7.19.0</openapi-generator-version>
         <openjpa-version>4.1.1</openjpa-version>
         <opensearch-rest-client-version>3.5.0</opensearch-rest-client-version>