feat(rn, security) added flag for controlling security options button visibility

react/features/base/flags/constants.js

  */
 export const LIVE_STREAMING_ENABLED = 'live-streaming.enabled';
 
+/**
+ * Flag indicating if lobby mode button should be enabled.
+ * Default: enabled.
+ */
+export const LOBBY_MODE_ENABLED = 'lobby-mode.enabled';
+
 /**
  * Flag indicating if displaying the meeting name should be enabled.
  * Default: enabled (true).
 /**
  * Flag indicating if the meeting password button should be enabled.
  * Note that this flag just decides on the button, if a meeting has a password
- * set, the password ddialog will still show up.
+ * set, the password dialog will still show up.
  * Default: enabled (true).
  */
 export const MEETING_PASSWORD_ENABLED = 'meeting-password.enabled';
  */
 export const RESOLUTION = 'resolution';
 
+/**
+ * Flag indicating if the security options button should be enabled.
+ * Default: enabled (true)
+ */
+export const SECURITY_OPTIONS_ENABLED = 'security-options.enabled';
+
 /**
  * Flag indicating if server URL change is enabled.
  * Default: enabled (true)

react/features/security/components/security-dialog/SecurityDialogButton.js

 import type { Dispatch } from 'redux';
 
 import { createToolbarEvent, sendAnalytics } from '../../../analytics';
+import {
+    getFeatureFlag,
+    LOBBY_MODE_ENABLED,
+    MEETING_PASSWORD_ENABLED,
+    SECURITY_OPTIONS_ENABLED
+} from '../../../base/flags';
 import { translate } from '../../../base/i18n';
 import { IconSecurityOff, IconSecurityOn } from '../../../base/icons';
+import { isLocalParticipantModerator } from '../../../base/participants';
 import { connect } from '../../../base/redux';
 import { AbstractButton, type AbstractButtonProps } from '../../../base/toolbox/components';
 import { toggleSecurityDialog } from '../../actions';
  * @returns {Props}
  */
 function mapStateToProps(state: Object) {
+    const { conference } = state['features/base/conference'];
+    const { hideLobbyButton } = state['features/base/config'];
     const { locked } = state['features/base/conference'];
     const { lobbyEnabled } = state['features/lobby'];
+    const lobbySupported = conference && conference.isLobbySupported();
+    const lobby = lobbySupported && isLocalParticipantModerator(state) && !hideLobbyButton;
+    const enabledFlag = getFeatureFlag(state, SECURITY_OPTIONS_ENABLED, true);
+    const enabledLobbyModeFlag = getFeatureFlag(state, LOBBY_MODE_ENABLED, true) && lobby;
+    const enabledMeetingPassFlag = getFeatureFlag(state, MEETING_PASSWORD_ENABLED, true);
 
     return {
-        _locked: locked || lobbyEnabled
+        _locked: locked || lobbyEnabled,
+        visible: enabledFlag || (enabledLobbyModeFlag || enabledMeetingPassFlag)
     };
 }