removed strange import in csv.kt

Author: Jolanrensen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/csv.kt

@@ -19,7 +19,6 @@ import org.jetbrains.kotlinx.dataframe.codeGen.DefaultReadCsvMethod
 import org.jetbrains.kotlinx.dataframe.codeGen.DefaultReadDfMethod
 import org.jetbrains.kotlinx.dataframe.impl.api.parse
 import org.jetbrains.kotlinx.dataframe.impl.io.readDelimImpl
-import org.jetbrains.kotlinx.dataframe.io.ColType.String
 import org.jetbrains.kotlinx.dataframe.util.AS_URL
 import org.jetbrains.kotlinx.dataframe.util.AS_URL_IMPORT
 import org.jetbrains.kotlinx.dataframe.util.AS_URL_REPLACE