log: Fix only case of debugLog outside assert

Looks like this slipped through the cracks, oops.

It is the only such call site, though.  The only other matches
for the following search:

  $ git grep -C12 -P '(?<!assert.)debugLog\('

are the function's definition, and two call sites that are enclosed
in IIFEs inside asserts.

Author: gnprice

lib/model/store.dart

@@ -1022,7 +1022,7 @@ class UpdateMachine {
             assert(debugLog('Lost event queue for $store.  Replacing…'));
             // This disposes the store, which disposes this update machine.
             await store._globalStore._reloadPerAccount(store.accountId);
-            debugLog('… Event queue replaced.');
+            assert(debugLog('… Event queue replaced.'));
             return;
 
           case Server5xxException():