build(deps): bump org.openapi.generator from 7.14.0 to 7.15.0

Bumps org.openapi.generator from 7.14.0 to 7.15.0.

---
updated-dependencies:
- dependency-name: org.openapi.generator
  dependency-version: 7.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -2,7 +2,7 @@
 java = "21"
 spring-boot = "3.5.5"
 spring-dependency-management = "1.1.7"
-openapi-generator = "7.14.0"
+openapi-generator = "7.15.0"
 openapi-tools = "0.2.7"
 swagger = "2.2.36"
 swagger-request-validator = "2.45.1"