[Themes]: Some properties in the grid summaries theme are inert

[simeonoff]

Description

Describe the issue.

• igniteui-angular version: v19.1.x (and older)
• browser: all

Steps to reproduce

1. Create a custom grid summary theme and try to pass $result-color
2. Observe the text color of result text

Result

The color is not being applied. It is being overwritten by the grid theme, specifically the --root-summaries-text-color property that comes from the grid theme.

Expected result

The summary theme should have higher priority than the grid theme.