libcmd/repl: Make AbstractNixRepl::create respect its store argument

The only reference (according to clangd) to this function also uses `openStore`,
so this is a no-op.

src/libcmd/repl.cc

@@ -839,7 +839,7 @@ std::unique_ptr<AbstractNixRepl> AbstractNixRepl::create(
 {
     return std::make_unique<NixRepl>(
         lookupPath,
-        openStore(),
+        std::move(store),
         state,
         getValues
     );