fix(deps): update dependency io.micronaut.test:micronaut-test-bom to v4.8.1

Author: renovate[bot]

gradle/libs.versions.toml

@@ -20,7 +20,7 @@ micronaut = "4.9.4"
 micronaut-docs = "2.0.0"
 micronaut-logging = "1.7.0"
 micronaut-serde = "2.15.0"
-micronaut-test = "4.7.0"
+micronaut-test = "4.8.1"
 micronaut-sourcegen = "1.8.2"
 micronaut-validation = "4.9.0"
 groovy = "4.0.24"