Update StructuredIrStreamReader to use Deserializer::get_num_log_events_deserialized()

[coderabbitai]

Description

The CLP core library has added a new getter method get_num_log_events_deserialized() to the Deserializer class (see y-scope/clp#1282). This method returns the number of deserialized log events so far.

Currently, StructuredIrStreamReader::get_num_events_buffered() maintains its own counter to track this information. This implementation can be updated to use the new getter method from the Deserializer class instead of maintaining a separate counter.

Tasks

• Update StructuredIrStreamReader::get_num_events_buffered() to use Deserializer::get_num_log_events_deserialized()
• Remove the separate counter maintained in StructuredIrStreamReader
• Test the updated implementation

References

• Original PR: feat(kv-ir): Add support for getting the number of log events read from the deserializer. clp#1282
• Comment: feat(kv-ir): Add support for getting the number of log events read from the deserializer. clp#1282 (comment)
• Requested by: @junhaoliao