Add sender key feature flag

preload.js

@@ -431,6 +431,7 @@ window.lokiFeatureFlags = {
   useSnodeProxy: !process.env.USE_STUBBED_NETWORK,
   useOnionRequests: true,
   useFileOnionRequests: false,
+  enableSenderKeys: false,
   onionRequestHops: 1,
 };
 

ts/components/session/SessionClosableOverlay.tsx

@@ -249,7 +249,8 @@ export class SessionClosableOverlay extends React.Component<Props, State> {
           />
         )}
 
-        {isClosedGroupView && (
+        {isClosedGroupView &&
+          window.lokiFeatureFlags.enableSenderKeys && (
             <div className="sealed-sender-toggle">
               <SessionToggle
                 active={Boolean(false)}