Connector offsets do not advance on transaction commit with filtered events when LOB enabled

In order to reproduce this issue, the connector must run indefinitely capturing changes for a table that does not change frequently. The offset SCN will not be advanced on transaction commits because the commit handler is never fired if the transaction consists of 0 events because they were all filtered out.

A transaction commit should always attempt to advance both the offset SCN (low watermark) and the commit SCN (high watermark) values.