Themes: Add updated Indigo themes for Slider, Text Area, and Tree

[simeonoff]

• Slider
• Text Area
• Tree

[AnjiManova]

Text Area

• Based on the Input component in the Text Area in the Invalid state, the helper text (hint) shouldn't have color coding. Applicable for Light and Dark mode and Warning and Correct state as well.

I have something else, but I'm not sure if it's relevant, so if it's not, ignore my comment. The drag indicator color does not change between the enabled and disabled states, but as far as I see, this is valid for all themes.

There is an additional comment related to the Text Area behaviour of saving the filled text and switching to Disabled, Read-only, Invalid, and so on, but we will create a separate issue for this, as the front-end developers recommended.

I saw nothing else as a discrepancy between the UI kit and the implementation.

[sbayreva]

Slider

1. The track should have 4px radius
2. The tickmarks should start right under the end of the track.

3.Тhe "Discrete Regions" should start from 0 as in the Handoff

4. The focus border of the thumb should be 3px

5. Тhe triangle of the label tooltip should have 12px height
   @andiesm813 please, check the comments and also, please check the behaviour of the Hover and Focus states - whether each element should have these states separately or when on Hover or Focused the whole component should be in that state.

[imincheva]

Tree:

• The left and right paddings should be fixed to 16px, 12px and 8px for large, medium and small respectively.
• The indentation should be 24px for all display densities.
• Might be irrelevant, but in the UI kits we have a specific stylisation for the hyperlinks, which I believe isn't implemented. Same for the custom chevron, don't know what the situation is with that.
• Тhis is probably some bug, but when I hover the first item, it doesn't inherit the correct color for the foreground in both light and dark mode. In the rest of the items this problem isn't apparent.

Edit: There are two things, which need to be applied in Angular as well:

• When a node is selected, it inherits a wrong color (--foreground-active). It should be fixed to (--foreground)
• The indentation should be 24px for all display densities.

[andiesm813]

Slider

1. The track should have 4px radius
2. The tickmarks should start right under the end of the track.

3.Тhe "Discrete Regions" should start from 0 as in the Handoff 4. The focus border of the thumb should be 3px 5. Тhe triangle of the label tooltip should have 12px height @andiesm813 please, check the comments and also, please check the behaviour of the Hover and Focus states - whether each element should have these states separately or when on Hover or Focused the whole component should be in that state.

@sbayreva
All your comments (1-4) are good. About #1 (radius of the track), it was also not implemented in Angular (from what i'm seeing).

About the hover and focus states, the current behavior in WC is the same as in the Angular component. Track and track base do hover together, but the thumb hovers separately, only when hovered on the thumb. So IMO it's all good as implemented now.