Disable --link flag in Micronaut-generated Dockerfiles

Configure MicronautDockerfile and NativeImageDockerfile tasks to set
useCopyLink=false, removing the COPY --link option from generated
Dockerfiles. This improves compatibility with Docker environments
that don't support BuildKit.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: taberj-git

UnityAuth/build.gradle

@@ -52,6 +52,15 @@ java {
 }
 
 graalvmNative.toolchainDetection = false
+
+tasks.withType(io.micronaut.gradle.docker.MicronautDockerfile).configureEach {
+  useCopyLink = false
+}
+
+tasks.withType(io.micronaut.gradle.docker.NativeImageDockerfile).configureEach {
+  useCopyLink = false
+}
+
 micronaut {
   runtime("netty")
   testRuntime("junit5")