Remove colouration of area when roof:colour input has focus

[CloCkWeRX]

Description

When I:

• Select a building way
• Add roof:colour as a key/input
• Focus on the input

Sometimes I am slightly mislead about the true colour of what I am seeing due to the light red mask atop the image. As I have focus, it is difficult to swap to wireframe mode with a keyboard shortcut such as w

I'd like ID to automatically do this for certain input, so that I'm making a more accurate judgement.

Alternatives
On focus, defaulting the input=colour being in 'eyedropper' mode would also solve a lot of this, encouraging me to make an accurate judgement.
https://developer.mozilla.org/en-US/docs/Web/API/EyeDropper_API however is not widely supported and the eyedropper behaviour isn't possible to trigger by plain HTML afaik.

Screenshots

Current state:
Roof colour looks slightly more "red-brown" than it actually is, due to the light red mask and active border:

Desired state:
For the selected way, if not all ways, swap to outline only mode when the roof:colour input has focus. Here we see the roof is actually dirty beige

On blur, revert to previous state.
In wireframe mode, obviously no transition needed.

This makes it more difficult to make subtle mistakes.

[anatolilavra-droid]

I'd like to work on this. My approach: when the roof:colour input
receives focus, store the current area fill mode and switch the map to
wireframe; restore the previous mode on blur. This reuses the existing
context.map().activeAreaFill() API.

Two questions before I open a PR:

1. Should this apply to all colour type fields, or only roof:colour?
2. You mention "for the selected way, if not all ways" — the current
   wireframe mode affects the whole map. Would a global switch be
   acceptable, or should it be scoped to the selection?

[CloCkWeRX]

I had intended it to be only roof:colour