fix base64 issue with cucumberjs 10+

[lerhum]

linked to #298

Describe the bug
In the JSON formatter output of multiple-cucumber-html-reporter, all attachments, including those initially attached as plain text strings, are now Base64 encoded. This uniform encoding approach leads to ambiguity for consumers of the report, as they cannot distinguish whether an attachment was originally a plain text string or a different file format.

To Reproduce
Steps to reproduce the behavior:

just generate a report based on cucumber 10.0.1 with some attachement (json/ text / image)

Expected behavior
The expected behavior was that string attachments would remain as plain text in the JSON formatter output, while other types of attachments would be Base64 encoded. This distinction would enable consumers to easily identify the nature of the attachments without additional processing.

Additional context
To resolve this issue, a decoding mechanism such as atob(embedding.data); should be implemented to correctly decode Base64 attachments before passing them to the report. This would ensure that plain text attachments maintain their original format in the JSON output.

[WasiqB]

@lerhum , can you please fix the failing test?

[martdo02]

If we are using atob, we need to escape the Non- ASCII chracters to avoid the Invalid character error.
embedding.data = decodeURIComponent(escape(embedding.data, 'base64'));

But since escape is depericated, try embedding.data = Buffer.from(embedding.data, 'base64') instead

[martdo02]

Also, decoding an image/png will break the image in the attachment. Use embedding.data = Buffer.from(embedding.data, 'base64') for any non image/png media type

[martdo02]

Try using embedding.data = Buffer.from(embedding.data, 'base64'); to solve the Invalid character issue

[WasiqB]

Changes are merged via #308