fix(http): fix encoding issue in multipart/form-data requests

[rezendeneto]

This PR addresses the issue of handling special characters in FormData requests (e.g. ü, ö, and ä). To provide a clearer understanding of the changes, I've prepared a code snippet, which you can view here: tutorialspoint snippet

[rezendeneto]

Hello! Can we please get a review on this PR?

This PR contains a minor code change that fixes the issue where a FormData can't be submitted with "special" characters like ö, ü and ä.

[JosefBredereck]

Does this also resolve the issue if the file name contains any of these special characters?

[rezendeneto]

@JosefBredereck good point! Since we know that os.writeBytes does not handle well special characters, I would assume that, if they appear in any of these calls, they wouldn't be encoded correctly:

[5uper]

looks like the same PR https://github.com/ionic-team/capacitor/pull/6730