Investigate Stencil Form Associated components

## Summary
From version 4.5, Stencil has support for Form Associated components: https://stenciljs.com/docs/form-associated

This could potentially provide an alternative method to the way we currently expose the underlying input field values on form submit

## 💬 Description

**Questions:**

Would this allow the removal of the hidden input controls that we currently have to add to ensure that date is posted correctly on form submit?
Would it be a breaking change? Or is there anything we could do to reduce that risk?
Would this make the “form” prop\attribute obsolete? Would it affect any other “form*” props attributes
Is it supported in all browsers we would need to support?

The purpose of this ticket is to identify answers to the above and evaluate if we should replace our existing mechanism with this approach. The output of this ticket should be a recommendation of whether to proceed & information on what changes would be required and to which components.

Start by reading the Stencil Form Associated components documentation linked in the issue and reviewing the current hidden input controls used for form submission. Evaluate browser support, breaking-change risks, the form prop and other form-related attributes, and identify affected components. Done means a recommendation on whether to proceed plus the required changes and components.

Written by the indexing model from the issue text.