[Gradle, JS] Remove source maps flags in IR

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/ir/KotlinJsIrTargetConfigurator.kt

@@ -126,7 +126,6 @@ open class KotlinJsIrTargetConfigurator(kotlinPluginVersion: String) :
 
     private fun KotlinJsOptions.configureOptions() {
         moduleKind = "umd"
-        sourceMap = true
     }
 
     override fun defineConfigurationsForTarget(target: KotlinJsIrTarget) {