Stop the test mocks deleting cryptLock

The mock routers freed the global crypt lock in their destructors, each
with a comment pointing at the reason: Router's constructor asserted the
global was null before allocating it, so a suite that built more than one
router had to hand it back. That assert is gone - the constructor now
reuses an existing lock, the same idiom as routingAuthCacheLock on the
next line - and nothing in src/ has ever freed it, so these deletes now
free a lock the mock does not own and leave the global null behind them.

test_admin_radio is where that bites: ~HamModeMockRouter runs from
tearDown, and the next test reaches AdminModule's receive path, which
takes LockGuard(cryptLock) - a null dereference now that the Portduino
Lock is a real mutex. The other six were the same hazard waiting for a
suite to add a test after them.

Co-Authored-By: Jonathan Bennett <jbennett@incomsystems.biz>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VeY5PczVYsxWNZhE2Cx4Sv

test/test_nodeinfo_send_window/test_main.cpp

@@ -82,14 +82,6 @@ class MockRouter : public Router
   public:
     MockRouter() { addInterface(std::unique_ptr<RadioInterface>(new StubRadioInterface())); }
 
-    // Router's constructor asserts cryptLock is null before allocating it, so a per-test router can
-    // only be rebuilt if the previous one hands the global back.
-    ~MockRouter()
-    {
-        delete cryptLock;
-        cryptLock = nullptr;
-    }
-
     ErrorCode send(meshtastic_MeshPacket *p) override
     {
         sentPackets.push_back(*p);