chore: Import external patches with replacements, b=no-bug, c=no-component

src/external-patches/firefox/native_macos_popovers.patch

@@ -131,7 +131,7 @@ diff --git a/toolkit/themes/shared/global-shared.css b/toolkit/themes/shared/glo
  /* Lightweight theme roots */
  
  :root[lwtheme] {
-   body,
+   .browser-toolbox-background,
    toolbar,
 diff --git a/widget/cocoa/nsCocoaWindow.h b/widget/cocoa/nsCocoaWindow.h
 --- a/widget/cocoa/nsCocoaWindow.h

src/external-patches/manifest.json

@@ -18,7 +18,8 @@
       // Specifically trying to target FeatureCallout.sys.mjs's change.
       // IMPORTANT: Make sure Feature callouts STILL use native popopvers when
       //    syncing from upstream, as this is a critical part of the patch.
-      "+            nonnativepopover=\"true\"": "+ "
+      "+            nonnativepopover=\"true\"": "+ ",
+      "body,": ".browser-toolbox-background,"
     }
   },
   {

src/zen/sessionstore/ZenSessionManager.sys.mjs

@@ -450,7 +450,8 @@ export class nsZenSessionManager {
       ];
     }
     for (const winData of initialState?.windows || []) {
-      winData.spaces = winData.spaces || this._migrationData?.spaces || [];
+      winData.spaces =
+        (winData.spaces?.length ? winData.spaces : this._migrationData?.spaces) || [];
       if (winData.tabs) {
         for (const tabData of winData.tabs) {
           let storeId = tabData.zenSyncId || tabData.zenPinnedId;