Refine native profile to use a classifier for the repackaged jar

This commit refines 80470f0b26 so that the 'repackage' goal of the
Spring Boot maven plugin uses a classifier. Previously, a regular
package with the profile fails as the Native Build Tools is trying to
use the repackaged archive as a regular jar file.

This is temporary as we'd like to explore other solutions, including
suggesting an additional option in the NBT plugin itself that uses the
regular classpath, rather than the produced jar.

See gh-30830

spring-boot-project/spring-boot-starters/spring-boot-starter-parent/build.gradle

@@ -232,6 +232,12 @@ publishing.publications.withType(MavenPublication) {
 											delegate.goal('aot-generate')
 										}
 									}
+									execution {
+										delegate.id('repackage')
+										configuration {
+											delegate.classifier('exec')
+										}
+									}
 								}
 							}
 							plugin {