bug(theme): M2 custom Palette - different colors and design since v20

[passee]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

v19

Description

Since angular v20 some components have different colors and styles.
We use our own palette and are still using M2 Theme.
Differences:

• Slide toggle has different design
• Slide toggle active checked icon color is black instead of white
• Paginator disabled buttons color is more prominent, less distinguishable to the active buttons

The palette is the exact same, such as the implementation of using m2 theme

Reproduction

v19: https://stackblitz.com/edit/aebaid8i-yxvqyhpq?file=src%2Fstyles.scss
v20: https://stackblitz.com/edit/vvmsxoxe-pfgpcfbr?file=src%2Fstyles.scss

i noticed that when using @include mat.all-component-theme($theme); in v20 instead of @include mat.all-component-colors($theme); the old slide toggle design is restored, but the colors are still off.

Expected Behavior

Slide toggle same design, colors and disabled paginator buttons same color with the same palette and theme

Actual Behavior

different design, colors

Environment

• Angular: v20
• CDK/Material: 20
• Browser(s): Chrome
• Operating System: Win11

[passee]

It could be possible that the state in v20 is correct or as intended but then i guess v19 is wrong. I would appreciate some clarity and unified design and colors in both versions

[crisbeto]

I think the M2 theme should still be included through all-component-themes. cc @andrewseguin