fix(deps): update dependency org.springdoc:springdoc-openapi-starter-webflux-ui to v2.8.4

Author: renovate[bot]

gradle/libs.versions.toml

@@ -7,7 +7,7 @@ simba = "2.6.2"
 cosec = "2.9.9"
 guava = "33.4.0-jre"
 commons-io = "2.18.0"
-springdoc = "2.8.3"
+springdoc = "2.8.4"
 hamcrest = "3.0"
 mockk = "1.13.16"
 jmh = "1.37"