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

Inizia tracciando l’implementazione di mat.theme-overrides e la generazione delle variabili tipografiche descritta nella riproduzione. Usa l’esempio body-small per verificare se un override abbreviato può aggiornare le sue proprietà separate senza duplicazione manuale. Il lavoro è completato quando la forma abbreviata produce le variabili tipografiche previste e i consumer dei componenti esistenti usano i valori sovrascritti.

Scritto dal modello di indicizzazione a partire dal testo della issue.