[bug] Preset blocks default config inconsistently

[this-gavagai]

frappe-ui includes a preset config file to align tailwindcss's defaults to the frappe design language. That's great. At present, however, the logic of the file is a bit strange. It extends the defaults for some classes (spacing, width, height, minWidth, minHeight, borderColor, typography) but replaces them for others (colors, borderRadius, boxShadow, container, fontSize, screens).

It is not clear whether this was deliberate, but it can lead to a very confusing experience for users. Some tailwind classes are blocked, while others pass through. The fix is easy, and I'm happy to submit a PR, but I am posting an issue first in case the maintainers have any opinions.