Fix crash when streaming file with Arabic chars

See: https://developer.android.com/reference/java/nio/charset/Charset.html#defaultCharset()

> Android note: The Android platform default is always UTF-8.

Author: mjmasn

android/src/main/java/com/RNFetchBlob/RNFetchBlobFS.java

@@ -21,9 +21,7 @@
 import com.facebook.react.modules.core.DeviceEventManagerModule;
 
 import java.io.*;
-import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
-import java.nio.charset.CharsetEncoder;
 import java.security.MessageDigest;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -325,9 +323,7 @@ else if(resolved == null) {
             boolean error = false;
 
             if (encoding.equalsIgnoreCase("utf8")) {
-                CharsetEncoder encoder = Charset.forName("UTF-8").newEncoder();
                 while ((cursor = fs.read(buffer)) != -1) {
-                    encoder.encode(ByteBuffer.wrap(buffer).asCharBuffer());
                     String chunk = new String(buffer, 0, cursor);
                     emitStreamEvent(streamId, "data", chunk);
                     if(tick > 0)