Login - LoginMainFooterLinksItem structure update

[kmcfaul]

Follow up to patternfly/patternfly-react#10107

Instead of passing properties to the component, the content will be passed directly via children. There should be enough info from the props to generate the children (if the component was "a" create a link or if it was a "button" use our plain variant Button) but I'm wondering if that is still making too many assumptions.