TextField: Always show password reveal icon

On a password text field, always show the password reveal icon, rather than waiting for some text to be written or "normal mode" to be toggled back and forth.

This makes usability better on devices with a virtual keyboard e.g. a Steam Deck, as opening the keyboard blocks anyother input.

For example while inputting a long wifi password on the network widget you'd want to check that you have it right character by character. With the actual behaviour you have to open the virtual keyboard, write a character, realise that the text is cloaked, close the keyboard, click on the reveal button, open the keyboard again and continue writing. If the reveal icon was enabled by default you would instantly see that the input is cloaked, so you would click to reveal the text, open the virtual keyboard and start inputting the password without stop.