message: Allow hiding "Sign Up" in the guest preview bar
  Hide the button when "UIFeature.registration" is set to false in
  Element's config.json.
  Fixes
diff: @@ -35,6 +35,8 @@ import InviteReason from "../elements/InviteReason";
  import { IOOBData } from "../../../stores/ThreepidInviteStore";
  import Spinner from "../elements/Spinner";
  import AccessibleButton from "../elements/AccessibleButton";
  +import { UIFeature } from "../../../settings/UIFeature";
  +import SettingsStore from "../../../settings/SettingsStore";
  const MemberEventHtmlReasonField = "io.element.html_reason";
  @@ -339,8 +341,10 @@ export default class RoomPreviewBar extends React.Component<IProps, IState> {
  }
  case MessageCase.NotLoggedIn: {
  title = _t("Join the conversation with an account");
  + if (SettingsStore.getValue(UIFeature.Registration)) {
  primaryActionLabel = _t("Sign Up");
  primaryActionHandler = this.onRegisterClick;
  + }
  secondaryActionLabel = _t("Sign In");
  secondaryActionHandler = this.onLoginClick;
  if (this.props.previewLoading) {
  