[BUG] Multiple connections opened on one serial port

[khoahoangqenergy]

Describe the bug
Clear and concise description of what the bug is.
When we have multiple devices daisy chained - with different modbus device IDs, under the same serial port, we have to make several slaves in modbus_serial.json config. However, we notice that for every slave instance, Thingsboard IoT Gateway opens up a new connection in the serial port, causing congestion and sometimes a delay in data being read on these devices under the same serial port.
Connector name (If bug in the some connector):
[Modbus Serial Connector]

Versions (please complete the following information):

• OS: [Ubuntu 18.04]
• Thingsboard IoT Gateway version [3.4.3]
• Python version[3.10]

[github-actions]

Hi @khoahoangqenergy.
Thank you for your interest in ThingsBoard IoT Gateway.
Your issue was registered, please wait for response from engineer.

IOTGW-171

[imbeacon]

Hi @khoahoangqenergy,

This issue fixed in the master branch, please try to use it or wait for the release.