IdsDropdown: readonly combined with typeahead doesn't gray the field

[fabiojpoli]

Describe the bug When set readonly as true and typeahead as well, the field is not disabled (gray).

To Reproduce

<ids-dropdown id="ids-dropdown-1" label="Dropdown" readonly typeahead="true">
  <ids-list-box id="ids-list-box-1">
    <ids-list-box-option value="opt1" id="opt1">Option One</ids-list-box-option>
    <ids-list-box-option value="opt2" id="opt2">Option Two</ids-list-box-option>
    <ids-list-box-option value="opt3" id="opt3">Option Three</ids-list-box-option>
    <ids-list-box-option value="opt4" id="opt4">Option Four</ids-list-box-option>
    <ids-list-box-option value="opt5" id="opt5">Option Five</ids-list-box-option>
    <ids-list-box-option value="opt6" id="opt6">Option Six</ids-list-box-option>
  </ids-list-box>
</ids-dropdown>

Expected behavior Fully disable(readonly) the field independently of the attribute applied if read only is true.

Version 1.4.2

Screenshots