Dropdown: NVDA failed to read correctly readonly

[arnauddem]

[x] bug report

Found using primereact 3.4.0, also found in release 4.2.2. Using various browser: Chrome 83.0.4103.97, Opera 68.0.3618.165, Firefox 77.0.1 Go to Dropdown widget showcase: https://primefaces.org/primereact/showcase/#/dropdown choose a city (Paris) from Basic dropdown.

Starts screen reader NVDA (I use version 2020.1), set focus on basic dropdown: screen reader said: 'edit read only subMenu blank' (see picture)

expected result is: 'edit read only subMenu Paris'.

'blank' word comes from created by renderKeyboardHelper(). I propose to set value of this input, then NVDA will be able to read/talk correct value. Here is a simple proposal (patch for release 3.4.0, may work only for read only dropdown ... need expert for full solution, thaks).