### Describe the bug

After upgrading msw from 1.x to 2.x `FormData` upload stopped working in tests. Looking at the debugging output, Axios doesn't append the `boundary` to the `Content-Type` header anymore.

The MSW team checked [1] this already on their side.

I tried to append the boundary manually to the header for debugging purposes, but that revealed another issue:
```
{ "Content-Type": "multipart/form-data; boundary=abc" }
```
ends in
```
Content-Type: multipart/form-databoundary=abc
```


[1] https://github.com/mswjs/msw/issues/1835


### To Reproduce

Checkout the msw reproducer at [1] and
```
cd examples/with-vitest
npm install
npm test
```


[1] https://github.com/pschyma/msw-examples/tree/axios-formdata-reproducer

### Code snippet

_No response_

### Expected behavior

As with msw the `boundary` is appended to `Content-Type` header.

### Axios Version

1.6.0

### Adapter Version

XHR

### Browser

jsdom

### Browser Version

_No response_

### Node.js Version

18.8.2

### OS

Linux

### Additional Library Versions

```bash
msw 2.0.x
vitest 0.34.6
```


### Additional context/Screenshots

_No response_
lib/helpers/isURLSameOrigin.js
host: urlParsingNode.host,
        search: urlParsingNode.search ? urlParsingNode.search.replace(/^\?/, '') : '',
        hash: urlParsingNode.hash ? urlParsingNode.hash.replace(/^#/, '') : '',
        hostname: urlParsingNode.hostname,
        port: urlParsingNode.port,
        pathname: (urlParsingNode.pathname.charAt(0) === '/') ?
          urlParsingNode.pathname :
          '/' + urlParsingNode.pathname
      };
    }
    originURL = resolveURL(window.location.href);
    /**
    * Determine if a URL shares the same origin as the current location
    *
    * @param {String} requestURL The URL to test
    * @returns {boolean} True if URL shares the same origin, otherwise false
    */
    return function isURLSameOrigin(requestURL) {
      const parsed = (utils.isString(requestURL)) ? resolveURL(requestURL) : requestURL;
      return (parsed.protocol === originURL.protocol &&
          parsed.host === originURL.host);
    };
  })() :
  
  (function nonStandardBrowserEnv() {
    return function isURLSameOrigin() {
      return true;
    };
  })();