Build: Fix artifacts signing for maven central

With gradle > 5.0 `publish()` helper call should be done before
`noDefaultJar()` or any other artifact hacks, otherwise singing plugin doesn't sign any jars

libraries/tools/kotlin-main-kts/build.gradle.kts

@@ -55,6 +55,8 @@ sourceSets {
     "test" { }
 }
 
+publish()
+
 noDefaultJar()
 
 val packJar by task<ShadowJar> {
@@ -98,5 +100,3 @@ dist(
 
 sourcesJar()
 javadocJar()
-
-publish()