Poor VeSTige performance

### System Information

Ubuntu 24.04
AMD Ryzen 3 2200G

### LMMS Version(s)

1.3.0-alpha.1.612+ge9848dbbb

### Bug Summary

I've recently had a lot of issues running large LMMS projects so i got into testing some stuff. From what i found every VST instrument loaded consumes about 1.5% of my CPU (R3 2200G 4X 3.50Ghz) even when on idle. This of course means that loading 20 or 30 of them (FX included) impacts performance really badly. The reason i think this is an issue is because no other DAW has this much of a performance hit when loading plugins as currently LMMS has and on top of that, even loading VST or LV2 plugins through Carla seems to cause less CPU load than loading them directly through VeSTige.

### Expected Behaviour

Plug-ins go to sleep when not in use and LMMS is able to handle a bunch of them without overloading the CPU

### Steps To Reproduce

Load any native linux VST you like through the VeSTige handler and check for CPU load through the system monitor during no playback with the default template.

### Screenshots


Start with the VeSTige handler and reproduce the report using a native Linux VST, the default template, and the system monitor while idle. Compare CPU usage with several loaded plug-ins and verify that idle projects no longer incur the reported per-plug-in load.

Written by the indexing model from the issue text.