feat(mat-card): add title-text-color to card-overrides

### Feature Description

It doesn't exactly make sense to allow subtitle-text-color in the override but not title...

Wouldn't we want the title to match the rest of the custom M3 theming?

I'd like to propose adding `title-text-color: color` to the mat.card-overrides

you end up with something like this otherwise:


### Use Case

```
@include mat.card-overrides((
title-text-color: var(--mat-sys-on-secondary),
subtitle-text-color: var(--mat-sys-on-secondary),
outlined-container-color: var(--mat-sys-secondary),
));
```
maybe even just a color option:

```
@include mat.card-overrides((
text-color: var(--mat-sys-on-secondary),
outlined-container-color: var(--mat-sys-secondary),
));
```

so that it all matches like this:


Locate the mat.card-overrides definition and the existing subtitle-text-color entry, then inspect how card title styles consume theme tokens. The issue leaves open whether to add title-text-color or a shared text-color option; done when the chosen override makes the title and subtitle colors match in the shown use case.

Written by the indexing model from the issue text.