FR(Theming):Typography override in theme-overrides

### 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

_No response_

### Description

when using `mat.theme-overrides((` I notice that the css variables created for typography require a one line definition but also each property has to be defined separately.

### Reproduction

```
@include mat.theme-overrides((
body-small: 400 1.125rem/1.6875rem Inter,
))
```
results in css variables

as you can see the one line definition gets replaced by my override but I have to do a one by one property replacement so that other components using body-small are not using the theme's default values.

```
@include mat.theme-overrides((
body-small: 400 1.125rem/1.6875rem Inter,
body-small-size: 1.125rem,
body-small-font: 'Inter Tight',
body-small-line-height: 1.6875rem,
body-small-weight: 400,
))
```

### Expected Behavior

It would be nice if we can just use `body-small: 400 1.125rem/1.6875rem Inter,` and that would also update the separate properties internally in the theme if is possible to extract those values (which I think it is).

### Actual Behavior

I feel like we have to over-define the same properties:

```
@include mat.theme-overrides((
body-small: 400 1.125rem/1.6875rem Inter,
body-small-size: 1.125rem,
body-small-font: 'Inter Tight',
body-small-line-height: 1.6875rem,
body-small-weight: 400,
))
```

### Environment

- Angular: 20.3.2
- CDK/Material: 20.2.4
- Browser(s): Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): MacOS

Beginne damit, die Implementierung von mat.theme-overrides und die in der Reproduktion beschriebene Generierung der Typografievariablen nachzuverfolgen. Verwende das Beispiel body-small, um zu prüfen, ob ein Override in Kurzschreibweise seine separaten Eigenschaften ohne manuelle Duplizierung aktualisieren kann. Fertig ist die Aufgabe, wenn die Kurzschreibweise die erwarteten Typografievariablen erzeugt und bestehende Komponentennutzer die überschriebenen Werte verwenden.

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