chore: migrate Button to @revoltchat/ui (#617)

* chore: start moving Button over

* fix: convert ServerIdentityModal

* fix: modal button styling

* fix: popover styles

* fix: clean up references to ui/*.*

* fix: button sizing

Co-authored-by: Ed L <beartechtalks@gmail.com>

src/context/intermediate/popovers/ModifyAccount.tsx

@@ -88,7 +88,7 @@ export function ModifyAccountModal({ onClose, field }: Props) {
                 {
                     onClick: onClose,
                     children: <Text id="app.special.modals.actions.cancel" />,
-                    plain: true,
+                    palette: "plain",
                 },
             ]}>
             {/* Preact / React typing incompatabilities */}