Remove explicit configuration of sonatype credentials

The project property that was being used is the default anyway.

gradle/plugins/src/main/kotlin/build.nexus-publish.gradle.kts

@@ -20,9 +20,6 @@ plugins {
 
 nexusPublishing {
  repositories {
- sonatype {
- username = project.provider { project.findProperty("sonatypeUsername") as String }
- password = project.provider { project.findProperty("sonatypePassword") as String }
- }
+ sonatype()
  }
 }