ABLM2 VST plugin can't connect to second plugin instance

### Bug Summary

ABLM2 VST plugin can't connect to second instance. I tested 32 and 64 bit version.
Demo can be downloaded from: https://www.tbproaudio.de/products/ablm
It's working in FL Studio Demo even on linux (wine 6.6 - needs core fonts from winetricks).

#### Steps to reproduce

1. Add ABLM2 effect
2. Add second instance of ABLM2
3. Change mode in second instance to Receive
4. -> See not connected in first instance

#### Expected behavior

ABLM2 should connect to first plugin instance.

#### Actual behavior

ABLM2 VST plugin can't connect.

#### Screenshot


#### Affected LMMS versions

Tested on stable 1.2 (windows) and current 1.3 master branch (linux).

#### Logs

Logs from linux machine

0024:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.

Starting detached.

unique ID: TB55

RemotePlugin::DebugMessage: inputs: 2  output: 2

RemotePlugin::DebugMessage: creating editor

RemotePlugin::DebugMessage: editor successfully created

0108:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.

0108:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.

0110:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.

0110:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.

Starting detached.

unique ID: TB55

RemotePlugin::DebugMessage: inputs: 2  output: 2

RemotePlugin::DebugMessage: creating editor

RemotePlugin::DebugMessage: editor successfully created

Start by reproducing the issue in LMMS with two ABLM2 VST instances, following the listed steps and reviewing the provided Linux logs. Trace the plugin-instance connection behavior and verify that changing the second instance to Receive connects it to the first.

Written by the indexing model from the issue text.