Extract Function: Drop extra space in modifier list

#KT-23274 Fixed

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/extractorUtil.kt

@@ -65,7 +65,9 @@ private fun buildSignature(config: ExtractionGeneratorConfiguration, renderer: D
         else -> CallableBuilder.Target.READ_ONLY_PROPERTY
     }
     return CallableBuilder(builderTarget).apply {
-        val modifiers = listOf(config.descriptor.visibility) + config.descriptor.modifiers.map { it.value }
+        val visibility = config.descriptor.visibility
+        val extraModifiers = config.descriptor.modifiers.map { it.value }
+        val modifiers = if (visibility.isNotEmpty()) listOf(visibility) + extraModifiers else extraModifiers
         modifier(modifiers.joinToString(separator = " "))
 
         typeParams(