Replace usage of `android.text.TextUtils` in `Address`

import java.util.List;

import java.util.regex.Pattern;

import com.fsck.k9.mail.helper.TextUtils;

import org.apache.james.mime4j.MimeException;

import org.apache.james.mime4j.codec.DecodeMonitor;

import org.apache.james.mime4j.codec.EncoderUtil;

import org.jetbrains.annotations.VisibleForTesting;

import timber.log.Timber;

import android.text.TextUtils;

import android.text.util.Rfc822Token;

import android.text.util.Rfc822Tokenizer;

package com.fsck.k9.mail.helper

object TextUtils {

    @JvmStatic

    fun isEmpty(text: String?) = text.isNullOrEmpty()

    @JvmStatic

    fun join(separator: String, items: Array<Any>): String {

        return items.joinToString(separator)

    }

}