[firebase_ml_vision] Add rawBytes to the Barcode class

[the-mars-rover]

The problem I am facing:
I need to scan barcodes which are in ISO 8859-1 (latin1) format. However, the rawValue property of the Barcode class has already been encoded using UTF-8 and contains some replacement characters (�). Consequently, I am unable to determine what the actual value of the data was.

Proposed Solution:
Add a rawBytes property to the Barcode class - populate this property using getRawBytes on Android and rawData on iOS. Then, in cases that the barcode follows formats other than UTF-8, rawBytes can be used with the applicable format.

Some problems which are similar to this (even though they are on different projects):

• Reading Binary Data rmtmckenzie/flutter_qr_mobile_vision#44 (comment)
• Barcode doesn't provide rawData as a byte array!~ googlesamples/android-vision#156

If there is a better solution to this problem I really would like some help.

[the-mars-rover]

Submitted a PR for this: #2368

[the-mars-rover]

Updated the linked PR by pulling in latest master

[dayron9110]

Any updates?

[dayron9110]

News?

[the-mars-rover]

Since the firebase_ml_vision plugin was discontinued, followers of this issue can be directed to flutter-ml/google_ml_kit_flutter#56