fix: restore isolation and auto commit

Author: sattvikc

src/main/java/io/supertokens/storage/postgresql/ConnectionPool.java

@@ -54,7 +54,6 @@ private synchronized void initialiseHikariDataSource() throws SQLException, Stor
         HikariConfig config = new HikariConfig();
         PostgreSQLConfig userConfig = Config.getConfig(start);
         config.setDriverClassName("org.postgresql.Driver");
-        config.setTransactionIsolation("TRANSACTION_SERIALIZABLE");
 
         String scheme = userConfig.getConnectionScheme();
 

src/main/java/io/supertokens/storage/postgresql/Start.java

@@ -459,6 +459,10 @@ protected <T> T startTransactionHelper(TransactionLogic<T> logic, TransactionIso
             throw e;
         } finally {
             if (con != null) {
+                con.setAutoCommit(true);
+                if (defaultTransactionIsolation != null) {
+                    con.setTransactionIsolation(defaultTransactionIsolation);
+                }
                 con.close();
             }
         }