Estilo do biblatex não respeita `indexsorttitle`

## Problema/Erro

**Qual o sistema operacional e versão que está utilizado**?
macOS Sonoma 14.4.1
**Qual versão do latex está utilizando**? (`latex --version`)
```
pdfTeX 3.141592653-2.6-1.40.26 (TeX Live 2024)
kpathsea version 6.4.0
Copyright 2024 Han The Thanh (pdfTeX) et al.
There is NO warranty. Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.43; using libpng 1.6.43
Compiled with zlib 1.3.1; using zlib 1.3.1
Compiled with xpdf version 4.04
```

**Você está utilizando alguma personalização**? Qual?
Não.

### Descrição do problema

Ao usar o estilo `abnt` com o `biblatex`, as referências são ordenadas por ordem alfabética. O `biblatex` provê um campo `indexsorttitle` que deveria ser considerado no momento da ordenação com preferência em relação ao `title`.

No meu caso, por exemplo, eu tenho um artigo em dez partes, todos com o título igual:
* Título do artigo, parte 1
* Título do artigo, parte 2
* …
* Título do artigo, parte 10

As referências estão sendo ordenadas incorretamente, porque o "parte 10" está vindo logo depois do "parte 1", por conta da ordenação alfabética.

* Título do artigo, parte 1
* Título do artigo, parte 10
* Título do artigo, parte 2
* …
* Título do artigo, parte 9

Eu tentei usar o `indexsorttitle` para corrigir essa ordenação, mas o resultado é o mesmo.

bib real e resultado

```bib
@article{butler-1884-inspiration-1-nature-and-manner-of-communication,
title = {Inspiration},
subtitle = {it's nature and manner of communication},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840108-V61-02.pdf},
editor = {Smith, Uriah},
pages = {24},
number = {2},
volume = {61},
date = {1884-01-08},
}

@article{butler-1884-inspiration-2-differences-in-degrees,
title = {Inspiration},
subtitle = {differences in degrees and manner of bestowment},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840115-V61-03.pdf},
editor = {Smith, Uriah},
pages = {41},
number = {3},
volume = {61},
date = {1884-01-15},
}

@article{butler-1884-inspiration-3-visions-and-dreams,
title = {Inspiration -- No. 3},
subtitle = {visions and dreams},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840122-V61-04.pdf},
editor = {Smith, Uriah},
pages = {57--58},
number = {4},
volume = {61},
date = {1884-01-22}
}

@article{butler-1884-inspiration-4-light-through-visions,
title = {Inspiration -- No. 4},
subtitle = {light through visions the principal source of bible inspiration},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840129-V61-05.pdf},
editor = {Smith, Uriah},
pages = {73--74},
number = {5},
volume = {61},
date = {1884-01-29},
}

@article{butler-1884-inspiration-5-the-word-of-the-lord,
title = {Inspiration -- No. 5},
subtitle = {the Word of the Lord came into men through visions},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840205-V61-06.pdf},
editor = {Smith, Uriah},
pages = {89--90},
number = {6},
volume = {61},
date = {1884-02-05}
}

@article{butler-1884-inspiration-6-poetic-and-historic,
title = {Inspiration -- No. 6},
subtitle = {how were the poetic and historical books of the Bible written?},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840415-V61-16.pdf},
editor = {Smith, Uriah},
pages = {249--250},
number = {16},
volume = {61},
date = {1884-04-15}
}

@article{butler-1884-inspiration-7-books-of-solomon-job-etc,
title = {Inspiration -- No. 7},
subtitle = {the books of Solomon, Job, etc},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840422-V61-17.pdf},
editor = {Smith, Uriah},
pages = {265--267},
number = {17},
volume = {61},
date = {1884-04-22},
}

@article{butler-1884-inspiration-8-in-what-sense,
title = {Inspiration -- No. 8},
subtitle = {in what sense are Scriptures inspired?},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840506-V61-19.pdf},
editor = {Smith, Uriah},
pages = {296--297},
number = {19},
volume = {61},
date = {1884-05-06},
}

@article{butler-1884-inspiration-9-is-there-imperfection,
title = {Inspiration -- No. 9},
subtitle = {is there any degree of imperfection in the revelations of God to man?},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840527-V61-22.pdf},
editor = {Smith, Uriah},
pages = {344--346},
number = {22},
volume = {61},
date = {1994-05-27},
}

@article{butler-1884-inspiration-10-conclusions,
title = {Inspiration -- No. 10},
indexsorttitle = {Inspiration -- No. 9b},
subtitle = {final conclusions and reflections},
author = {Butler, George Ide},
journal = {The Review and Herald},
_url = {https://documents.adventistarchives.org/Periodicals/RH/RH18840603-V61-23.pdf},
editor = {Smith, Uriah},
pages = {361--362},
number = {23},
volume = {61},
date = {1884-06-03},
}
```