Surge XT in Carla Rack produces no sound after exit/reload song

### System Information

Linux Mint

### LMMS Version(s)

Version 1.3.0-alpha.1.695+g01294192c (Linux/x86_64, Qt 5.15.3, GCC 11.4.0).

### Most Recent Working Version

_No response_

### Bug Summary

Using Carla Rack to host Surge XT works fine, but if I save and close, then reopen LMMS and load the song, Surge XT produces no audio output even when notes are played. The output meters in the Surge XT GUI show no movement.

### Expected Behaviour

The Surge XT plugin should be properly reinstantiated and notes should play after song is reloaded.

### Steps To Reproduce

1. Add Carla Rack to new song
2. Add Surge XT to Carla Rack
3. Add notes to MIDI track
4. Save song
5. Quit LMMS
6. Load song in new instance of LMMS

### Logs

dto@thexder:~/src/lmms$ ./lmms
Lv2 plugin SUMMARY: 226 of 266 loaded in 127 msecs.
For details about not loaded plugins, please set
environment variable "LMMS_LV2_DEBUG" to nonempty.
Blocked Lv2 Plugins: 11 of 266
If you want to enable them (dangerous!), please set
environment variable "LMMS_ENABLE_BLOCKED_PLUGINS" to nonempty.
Connection established.

Stream successfully created

lmms::gui::TrackContentWidget(0x5621ce124ef0) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce147df0) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621cd8b99e0) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce352400) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621cde87290) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce381640) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce1f2e00) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce1343f0) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce4034f0) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621ce1507a0) does not have a property named "gridColor"
lmms::gui::TrackContentWidget(0x5621cec07240) does not have a property named "gridColor"
[carla] Plugin UI wants a feature that is not supported (ignored):
http://lv2plug.in/ns/ext/options#interface
[carla] Will use LV2 X11 UI for 'Surge XT'
[carla] Plugin requested value for 'https://surge-synthesizer.github.io/lv2/surge-xt:Program' which is not available

### Screenshots / Minimum Reproducible Project

_No response_

### Please search the issue tracker for existing bug reports before submitting your own.

- [X] I have searched all existing issues and confirmed that this is not a duplicate.

Reproduce the save, quit, reload, and playback sequence using Carla Rack with Surge XT, then inspect the reload path alongside the reported LMMS logs, especially the missing Surge XT Program value. Done means the plugin is reinstantiated with audio output and its meters respond to notes after reopening the song.

Written by the indexing model from the issue text.