Updated RemoveOldestFilesBeforeFull to fall back on working directory when no archive directories are found

Author: ritchiecarroll

Source/Libraries/Adapters/openHistorian.Adapters/LocalOutputAdapter.cs

@@ -887,7 +887,7 @@ private void RemoveOldestFilesBeforeFull()
             try
             {
                 // Check if any target archive destination has enough disk space
-                foreach (string path in m_archiveDirectories)
+                foreach (string path in m_archiveDirectories ?? [WorkingDirectory])
                 {
                     FilePath.GetAvailableFreeSpace(path, out long freeSpace, out _);