FormData cannot be correclty sent when call is made from a web worker

[stillgbx]

Describe the bug

FormData cannot be correclty sent when call is made from a web worker.
Content-Type request header seems incorrect because it's not deleted by axios to let the browser set the header.
isStandardBrowserEnv does not detect that the call is made from a web worker.

Changing isStandardBrowserEnv doesn't seem enough because other(s) part(s) of the code (like in isURLSameOrigin.js) rely on the result to use document (which is therefore not available in a web worker).

To Reproduce

Send FormData from a Web Worker.

Expected behavior

FormData should be sent correctly (like in v 0.26.1).

Environment

• Axios Version >= 0.27.0
• Browser : all
• OS : all

Additional context/Screenshots

[DigitalBrainJS]

Fixed in #5139