add type="submit" to bx-btn

[fedorzajac]

The problem

to be able to use bx-btn as native form element (preferably other elements as well) with carbon style and features. and not be dependent on any external js apart from js provided by carbon-web-components for easier incorporation into rails framework.

The solution

to be able to pass type="submit" into inner shadowed button element. like

<bx-btn type="submit"> 
or
<bx-btn submit>

### Application/website

internal

### Business priority

Low Priority = release date is not dependent on fix or not upcoming

### What time frame would this ideally be needed by (if applicable)

_No response_

### Examples

_No response_

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/carbon-design-system/carbon-for-ibm-dotcom/blob/main/.github/CODE_OF_CONDUCT.md)
- [X] I checked the [current issues](https://github.com/carbon-design-system/carbon-for-ibm-dotcom/issues) for duplicate issues

[stale]

We've marked this issue as stale because there hasn't been any activity for 60 days. If there's no further activity on this issue in the next three days then we'll close it. You can keep the conversation going with just a short comment. Thanks for your contributions.

[kennylam]

Should match types available in React component.

/**
  * Optional prop to specify the type of the Button
  */
  type: PropTypes.oneOf(['button', 'reset', 'submit']),