3.3.x: Bump org.springframework.boot from 3.3.4 to 3.3.9

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 3.3.4 to 3.3.9.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](https://github.com/spring-projects/spring-boot/compare/v3.3.4...v3.3.9)

---
updated-dependencies:
- dependency-name: org.springframework.boot
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

settings.gradle

@@ -19,7 +19,7 @@ pluginManagement {
 		id 'io.spring.nohttp' version '0.0.11'
 		id 'io.spring.javaformat' version '0.0.43'
 		id 'org.asciidoctor.jvm.convert' version '3.3.2'
-		id 'org.springframework.boot' version '3.3.4'
+		id 'org.springframework.boot' version '3.3.9'
 	}
 	repositories {
 		gradlePluginPortal()