gh-14100: restore workspace routing for extension-opened tabs with explicit containers (gh-14102)

Co-authored-by: pokeshah <89949620+pokeshah@users.noreply.github.com>

src/zen/spaces/ZenSpaceManager.mjs

@@ -3005,7 +3005,8 @@ class nsZenWorkspaces {
 
     if (
       triggeringPrincipal &&
-      triggeringPrincipal.isAddonOrExpandedAddonPrincipal
+      triggeringPrincipal.isAddonOrExpandedAddonPrincipal &&
+      typeof userContextId === "undefined"
     ) {
       return [userContextId, false, undefined];
     }