Slew distortion causes click when exporting

### System Information

Linux core2 6.19.10-arch1-1 #1 SMP PREEMPT_DYNAMIC Thu, 26 Mar 2026 19:20:28 +0000 x86_64 GNU/Linux

### LMMS Version(s)

1.3.0-alpha.1.968+6f50f90 (Linux/x86_64, Qt 5.15.18, GCC 15.2.1 20260209)

### Most Recent Working Version

_No response_

### Bug Summary

Exporting a song in which slew distortion is used with a non-centered "Bias" value causes audible clicks at the start.

Workarounds attempted which did not work:
- changing the value of "Keep effects running even without input";
- disabling "DC remover" in the plugin UI;
- reloading LMMS and exporting the track without playing - this one works sometimes, though that isn't the case for the minimum reproducible project I'm sending here;

### Expected Behaviour

The clicks should not be present.

### Steps To Reproduce

1. Open the minimum reproducible project.
2. Export it to a file.
3. After exporting, a click will be heard, and upon opening the exported file another click will be present at the start.

### Logs

Here are the exported files. I exported it twice - in both cases there was a click at the start, but they sound different.

[exp1.mp3](https://github.com/user-attachments/files/26980321/exp1.mp3)
[exp2.mp3](https://github.com/user-attachments/files/26980322/exp2.mp3)

### Screenshots / Minimum Reproducible Project

[Minimum reproducible project](https://github.com/user-attachments/files/26980337/slew_bug.zip) (zipped because github was complaining)

### 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.

Start by opening the attached minimum reproducible project in LMMS and reproducing an export with Slew Distortion and a non-centered Bias; no source files or tests are named. Done means exporting the project no longer produces audible clicks at the start of the output.

Written by the indexing model from the issue text.