implement setSourceBytes for web

[lucasdidur]

Checklist

• I made sure that the issue I am raising doesn't already exist

Use case / Problem

Play audio offline from bytes in cache.

Proposal / Solution

Implement setSourceBytes

Example Code

Example Code

void main() {
}

Affected platforms

web

Platform details

No response

Audio Files/URLs/Sources

No response

Mockups

No response

Related issues / more information

No response

Working on PR

no way

[lucasdidur]

Until is implement, we can use something like this:

String url = "data:audio/mp3;base64," + base64Encode(widget.audioBytes!);
source = UrlSource(url);

[Gustl22]

See #1269. Another possible implementation is also provided in #1681