test(adminui): #871 reaper not-a-guid database name unique per run

The fixed name lives on the SQL Server shared by every checkout and CI, so a
concurrent run's create or finally-drop could collide (failed once in the
local pre-push suite, 3/3 green on rerun; cause plausible, not proven).

Claude-Session: https://claude.ai/code/session_01GT67AD99zQQqpLCVm3p7xk

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/SqlTestDatabaseReaperTests.cs

@@ -103,7 +103,9 @@ public sealed class SqlTestDatabaseReaperTests
         // what bounds the character set of every candidate: without it a database named
         // "<prefix><aged timestamp>_" + arbitrary text would be fed to the drop statement, and before the
         // statement was parameterised that was a second-order injection running as sa.
-        var notAGuid = $"{AdminUiSqlServer.TestDatabasePrefix}20250101000000_notaguid";
+        // Unique per run: the SQL Server is shared by every checkout and CI, and a fixed name collided with a
+        // concurrent run's create / finally-drop. Digits only after "notaguid_", so it can never parse as a GUID.
+        var notAGuid = $"{AdminUiSqlServer.TestDatabasePrefix}20250101000000_notaguid_{Environment.ProcessId}_{Random.Shared.Next(1_000_000)}";
 
         CreateDatabase(master, notAGuid);