The foreground color in datagrid cells now use Ink's

--ink-c-data-table-body-fg token, which gives us a better color for

datagrids on dark mode. This is off-white, which contrasts better with

the background than pure white, making it easier to read the datagrid.

Tested locally, verifying that the colors in the CSS variable were

reflected in the datagrid by altering the variable at runtime.