fix(material/core): handle hues inferred as numbers (#23237)
fix(material/core): handle hues inferred as numbers (#23237)

We have some hues that start with a number (e.g. `700-contrast`), which can break the map lookup in `get-color-from-palette`, because Sass infers them as numbers.

These changes make it so that the key is cast to a string before we do the lookup.

Fixes #23230.
crisbeto/material2,josephperrott/material2,josephperrott/material2,josephperrott/material2,crisbeto/material2,crisbeto/material2,josephperrott/material2,angular/components,angular/components,josephperrott/material2,angular/components,angular/components,crisbeto/material2