### Describe the issue

I set `axios.defaults.headers.common['Content-Type'] = 'application/json'`. When firing a `axios.patch` request (without a config), the request uses `application/x-www-form-urlencoded` instead.

### Example Code

```js
// This does not work as expected:
axios.defaults.headers.common['Content-Type'] = 'application/json'

// This does:
axios.defaults.headers.common['Content-Type'] = 'application/json'
axios.defaults.headers.patch['Content-Type'] = 'application/json'
```


### Expected behavior

I expected POST requests to use `axios.defaults.headers.common`, too.

I think this is where the problem (or intended behaviour) comes from: https://github.com/axios/axios/blob/3f53eb6960f05a1f88409c4b731a40de595cb825/lib/core/dispatchRequest.js#L46

### Axios Version

1.4.0

### Adapter Version

_No response_

### Browser

Firefox

### Browser Version

116.0.3 (64-bit)

### Node.js Version

_No response_

### OS

_No response_

### Additional Library Versions

_No response_

### Additional context/Screenshots

_No response_
lib/defaults/index.js
if (utils.isString(rawValue)) {
    try {
      (parser || JSON.parse)(rawValue);
      return utils.trim(rawValue);
    } catch (e) {
      if (e.name !== 'SyntaxError') {
        throw e;
      }
    }
  }
  return (encoder || JSON.stringify)(rawValue);
}
const defaults = {
  transitional: transitionalDefaults,
  adapter: ['xhr', 'http'],
  transformRequest: [function transformRequest(data, headers) {
    const contentType = headers.getContentType() || '';
    const hasJSONContentType = contentType.indexOf('application/json') > -1;
    const isObjectPayload = utils.isObject(data);
    if (isObjectPayload && utils.isHTMLForm(data)) {
      data = new FormData(data);
    }
    const isFormData = utils.isFormData(data);
    if (isFormData) {