Crash when interacting with the song editor while automating solos between two mixer channels

### System Information

Windows 11 24H2 Build 26100.2033

### LMMS Version(s)

1.3.0-alpha.1.768+pr5147.ga94c8f1c0 (win32/x86_64, Qt 5.15.2, MSVC 192930154)

### Most Recent Working Version

_No response_

### Bug Summary

When interacting with the song editor window while automating two mixer channels' solo, there's a chance that LMMS can crash.

### Expected Behaviour

Not crash

### Steps To Reproduce

1. Open the attached project in LMMS
2. Play to the point of the automation, then click repeatedly.
3. Repeat step 2 until the program crashes

### Logs

WinDbg crash dump from !analyze -v

*******************************************************************************

*                                                                             *

*                        Exception Analysis                                   *

*                                                                             *

*******************************************************************************


*** WARNING: Unable to verify checksum for lmms.exe

*** WARNING: Unable to verify checksum for SDL2.dll

KEY_VALUES_STRING: 1

    Key  : Analysis.CPU.mSec

    Value: 1593

    Key  : Analysis.Elapsed.mSec

    Value: 4209

    Key  : Analysis.IO.Other.Mb

    Value: 0

    Key  : Analysis.IO.Read.Mb

    Value: 0

    Key  : Analysis.IO.Write.Mb

    Value: 0

    Key  : Analysis.Init.CPU.mSec

    Value: 515

    Key  : Analysis.Init.Elapsed.mSec

    Value: 3730

    Key  : Analysis.Memory.CommitPeak.Mb

    Value: 139

    Key  : Analysis.Version.DbgEng

    Value: 10.0.27704.1001

    Key  : Analysis.Version.Description

    Value: 10.2408.27.01 amd64fre

    Key  : Analysis.Version.Ext

    Value: 1.2408.27.1

    Key  : Failure.Bucket

    Value: HEAP_CORRUPTION_ACTIONABLE_BlockNotBusy_DOUBLE_FREE_80000003_ucrtbase.dll!free_base

    Key  : Failure.Hash

    Value: {acbee290-6526-0d11-a472-1fa34480839d}

    Key  : Timeline.OS.Boot.DeltaSec

    Value: 40509

    Key  : Timeline.Process.Start.DeltaSec

    Value: 296

    Key  : WER.OS.Branch

    Value: ge_release

    Key  : WER.OS.Version

    Value: 10.0.26100.1

    Key  : WER.Process.Version

    Value: 0.0.0.0

FILE_IN_CAB:  lmms-crash.dmp

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

CONTEXT:  (.ecxr)

rax=0000000000000000 rbx=00000000c0000374 rcx=d005898145be0000

rdx=00007ff86f5a51c3 rsi=0000000000000001 rdi=00007ff8d470b0e0

rip=00007ff8d45dc7e8 rsp=0000001517afb930 rbp=0000001517afbd00

 r8=00007ff873c521f8  r9=0000000000000001 r10=0000001517afb210

r11=0000000000000002 r12=0000000000000000 r13=0000000000000000

r14=0000018c00260000 r15=0000018c07058df0

iopl=0         nv up ei pl nz na pe nc

cs=0033  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00000200

ntdll!RtlReportCriticalFailure+0x68:

00007ff8`d45dc7e8 cc              int     3

Resetting default scope

EXCEPTION_RECORD:  (.exr -1)

ExceptionAddress: 00007ff8d45dc7e8 (ntdll!RtlReportCriticalFailure+0x0000000000000068)

   ExceptionCode: 80000003 (Break instruction exception)

  ExceptionFlags: 00000000

NumberParameters: 1

   Parameter[0]: 0000000000000000

PROCESS_NAME:  lmms.exe

ERROR_CODE: (NTSTATUS) 0x80000003 - {EXCEPTION}  Breakpoint  A breakpoint has been reached.

EXCEPTION_CODE_STR:  80000003

EXCEPTION_PARAMETER1:  0000000000000000

ADDITIONAL_DEBUG_TEXT:  Followup set based on attribute [Heap_Error_Type] from Frame:[0] on thread:[PSEUDO_THREAD] ; Followup set based on attribute [Is_ChosenCrashFollowupThread] from Frame:[0] on thread:[PSEUDO_THREAD]

FAULTING_THREAD:  ffffffff

STACK_TEXT:  

00000000`00000000 00000000`00000000 ucrtbase!free_base+0x0

STACK_COMMAND:  !heap ; ** Pseudo Context ** ManagedPseudo ** Value: ffffffff ** ; kb

SYMBOL_NAME:  ucrtbase!free_base+0

MODULE_NAME: ucrtbase

IMAGE_NAME:  ucrtbase.dll

FAILURE_BUCKET_ID:  HEAP_CORRUPTION_ACTIONABLE_BlockNotBusy_DOUBLE_FREE_80000003_ucrtbase.dll!free_base

OS_VERSION:  10.0.26100.1

BUILDLAB_STR:  ge_release

OSPLATFORM_TYPE:  x64

OSNAME:  Windows 10

IMAGE_VERSION:  10.0.26100.1882

FAILURE_ID_HASH:  {acbee290-6526-0d11-a472-1fa34480839d}

Followup:     MachineOwner

### Screenshots / Minimum Reproducible Project

* [debit debug.zip](https://github.com/user-attachments/files/17475658/debit.debug.zip)

If needed, I have multiple crash dumps of different projects that have the same issue. I can provide them by request of the maintainers

### 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 debit debug.zip project in LMMS and reproducing the crash while the song editor is active and solo automation runs between two mixer channels. Use the provided WinDbg heap-corruption output to investigate the song editor, mixer, and automation interaction; done means repeated interaction no longer crashes LMMS.

Written by the indexing model from the issue text.