LoginPage - add props to make username and password optional

[adamviktora]

Is this a new component or an extension of an existing one?
LoginPage

Describe the feature
Username and password form fields shoud not have the required prop hardcoded, but instead it should be configurable with props (required should still be the default though).

Are there visuals for this feature? If applicable, please include examples for each state and for varying widths

Original request from Slack: https://patternfly.slack.com/archives/C4FM977N0/p1729092084147469