core: do early setup check for arguments with '=' too

Follow-up for d2ebd50d7f

We now modify our cmdline to use '=' for all arguments,
but didn't change early setup check to work with that.
So every daemon-reexec does a full setup, thus breaking
running user sessions.

Fixes #27106

src/core/main.c

@@ -2744,7 +2744,7 @@ static bool early_skip_setup_check(int argc, char *argv[]) {
         for (int i = 1; i < argc; i++)
                 if (streq(argv[i], "--switched-root"))
                         return false; /* If we switched root, don't skip the setup. */
-                else if (streq(argv[i], "--deserialize"))
+                else if (startswith(argv[i], "--deserialize"))
                         found_deserialize = true;
 
         return found_deserialize; /* When we are deserializing, then we are reexecuting, hence avoid the extensive setup */