Actually create readonly connection when asked

Emby.Server.Implementations/Data/BaseSqliteRepository.cs

@@ -100,7 +100,7 @@ namespace Emby.Server.Implementations.Data
 
         protected SqliteConnection GetConnection(bool readOnly = false)
         {
-            var connection = new SqliteConnection($"Filename={DbFilePath}");
+            var connection = new SqliteConnection($"Filename={DbFilePath}" + (readOnly ? ";Mode=ReadOnly" : string.Empty));
             connection.Open();
 
             if (CacheSize.HasValue)