test(process_registry): pin that scope argv never emits OOMPolicy

The spawn_local systemd test asserted the property was present; it now
asserts the invariant the fix establishes (no OOMPolicy= on a transient
scope), so a reintroduction fails here instead of on older systemd hosts.

tests/tools/test_process_registry.py

@@ -1956,7 +1956,10 @@ class TestSystemdCgroupIsolation:
             if value == "--property"
         ]
         assert "MemoryAccounting=yes" in properties
-        assert "OOMPolicy=kill" in properties
+        # systemd rejects OOMPolicy= on transient --scope units across the versions
+        # users run (239/245/249, #102486); emitting it fails the probe and every
+        # cron worker dispatch. MemoryMax + MemoryAccounting carry the isolation.
+        assert not any(p.startswith("OOMPolicy=") for p in properties), properties
         memory_max = next(
             value for value in properties if value.startswith("MemoryMax=")
         )