Review ClimateMap Mobile Menu

>Removed max-width constraint from Section component to ensure full-width mobile display by removing the fixed prop.

I doubt that `fixed` in `Section` was the issue @kelvinkipruto; how come Section is used in other apps such as https://cfa.dev.codeforafrica.org and they don't have this issue?

Looking at the [code](https://github.com/CodeForAfrica/ui/blob/3049c841386644c4eaa90eec9f8833655f8edf3a/packages/commons-ui-core/src/Section/Section.js#L18-L27), `maxWidth` is only set if there is `contentWidths.value`. Mobile i.e. `xs` doesn't have `contentWidths.value` [defined](https://github.com/CodeForAfrica/ui/blob/a55a70d4ca50fa71225612b624c2fac7ab71b73b/apps/climatemappedafrica/src/theme/index.js#L133-L138).

_Originally posted by @kilemensi in https://github.com/CodeForAfrica/ui/issues/1079#issuecomment-2751190449_