feat: Dont restore sidebar if window-sync is disabled, b=no-bug, c=no-component

src/zen/sessionstore/ZenSessionManager.sys.mjs

@@ -312,6 +312,9 @@ export class nsZenSessionManager {
    *        The initial session state read from the session file, possibly modified by onFileRead.
    */
   onCrashCheckpoints(initialState) {
+    if (!lazy.gWindowSyncEnabled) {
+      return;
+    }
     // When we don't have browser.startup.page set to resume session,
     // we only want to restore the pinned tabs into the new windows.
     if (this.#shouldRestoreOnlyPinned && !this.#shouldRestoreFromCrash && this.#sidebar?.tabs) {

surfer.json

@@ -20,7 +20,7 @@
       "brandShortName": "Zen",
       "brandFullName": "Zen Browser",
       "release": {
-        "displayVersion": "1.18.6b",
+        "displayVersion": "1.18.7b",
         "github": {
           "repo": "zen-browser/desktop"
         },