[Gradle] Don't create another transformation task for commonMain source set

when compatibility variant enabled. commonMain have to be compiled
at least two times. One time to klib and second time to legacy metadata.
In both cases it should have correct classpath.

^KT-49933

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/metadata/KotlinMetadataTargetConfigurator.kt

@@ -336,11 +336,11 @@ class KotlinMetadataTargetConfigurator :
         val project = compilation.target.project
         val sourceSet = compilation.defaultSourceSet
 
-        val transformationTask = project.registerTask<MetadataDependencyTransformationTask>(
-            transformGranularMetadataTaskName(compilation.name),
+        val transformationTask = project.locateOrRegisterTask<MetadataDependencyTransformationTask>(
+            transformGranularMetadataTaskName(sourceSet.name),
             listOf(sourceSet)
         ) {
-            it.description =
+            description =
                 "Generates serialized dependencies metadata for compilation '${compilation.name}' of target '${compilation.target.name}' (for tooling)"
         }