Upgrade to Jetty Reactive HTTPClient 1.1.12

Closes gh-31740

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -930,7 +930,7 @@ bom {
 			]
 		}
 	}
-	library("Jetty Reactive HTTPClient", "1.1.11") {
+	library("Jetty Reactive HTTPClient", "1.1.12") {
 		prohibit("[2,)") {
 			because "it uses the jakarta.* namespace"
 		}