[Light] Tree expand toggle not visible when selected

[gquintana]

Describe the bug
When using the Atom One Light theme, the icon used to fold/unfold a tree item is not visible when selected

To Reproduce
Steps to reproduce the behavior:

1. User Atom Light Theme
2. In the Project view, select an item in the tree
3. Observe the grey "V" or ">" icon can hardly be seen with blue selection background

Screenshots

Application:
IntelliJ