[FormField]: clearable set once on the form field, shared by DateField and TimeField

[ly-tempel-bitweb]

Problem

clearable exists twice for the same visible affordance. tedi-form-field has one (default false) that renders .tedi-form-field__clear, and tedi-time-field has its own (default true) that renders .tedi-time-field__clear in its action row. A consumer wrapping a time field in <tedi-form-field clearable> gets two clear buttons in the same box, and there is no single place to turn the affordance on or off.

Solution

• Add clearable to FieldContext, so the control reads the wrapper's setting instead of declaring its own.
• tedi-form-field's clearable defaults to true and accepts a bare clearable attribute.
• Date and time fields resolve clearable() ?? fieldContext?.clearable() ?? true, the same pattern fix(form-field): wrapper is not required by controls anymore #612 #617 uses for size. Inside a form field, set it on the wrapper; the control's own input exists for standalone use and overrides the wrapper when set.
• Add optional ownsClearButton to FormFieldControl. Date and time set it, so the field skips its generic clear button — their button cannot move into form-field, because the picker button beside it is the overlay's anchor and the design puts clear before it in the action row.
• Storybook: group size and clearable under Form Field inputs for both fields, matching TextField, so wrapper-owned args read separately from the control's own.

BREAKING CHANGE: tedi-form-field's clearable now defaults to true, so fields that previously showed no clear button now show one once they have a value, and the form field renders its own surface box around text fields and textareas. Pass [clearable]="false" to opt out.

[ly-tempel-bitweb]

It was redecided that clearable should be true by default for all form elements.