Modbus bridge didn't begin at boot

[jeroenst]

Description:

The ModbusBridgeBegin was not called at boot init causing ModbusBridge not working after reboot.

Related issue (if applicable): fixes #9586 (comment)

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.4.9
• The code change is tested and works with Tasmota core ESP32 V.2.0.4 N/A
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass