RTL paragraph in LTR footnote results in odd margins

In an English text, I have some Arabic passages. Now I have the special case that there is an Arabic paragraph in a (English) footnote. I have tried two variants, but neither produce satisfying results:

When marking the text using textarabic{}, the second line of the paragraph is left aligned, which is unnatural for Arabic text.

When using begin{Arabic}end{Arabic}, the text direction is changed to RTL, which makes the text flow correctly, but the margins are now odd: The text reaches into the left margin which is reserved to the footnote, while there is an additional margin on the right.

A minimal example is below.

Is there a variant that sets the Arabic paragraph correctly as RTL (i.e., starting the second line on the right), while respecting the overall margins of the footnote?

documentclass[english, a4paper]{scrartcl}
usepackage{unicode-math}
defaultfontfeatures{Scale=MatchLowercase}
defaultfontfeatures[rmfamily]{Ligatures=TeX,Scale=1}
setmainfont[]{Charis SIL}
setsansfont[]{Charis SIL Compact}
%% languages/scripts
newfontfamilyarabicfont[Script=Arabic]{Scheherazade}
usepackage{polyglossia}
setmainlanguage[]{english}
setotherlanguage[]{arabic}
usepackage{bidi}

begin{document}
%% No additional space between sentences
frenchspacing

Christians are
compared to emph{goim} and are also accused of heresy (emph{herejía}),
mainly because of their inability to understand revelation. They are
compared to donkeys (emph{ḥimār}): an ``asno ke lieba libros''
(``donkey that carries books'').footnote{Cardaillac (1972, 2:41),
  Madrid, National Library of Spain, Aljamiado 4944, f.~45f. Algiers,
  National Library of Algeria, Ar. 1557, p.~57, lines 7--8.

  textarabic{فسجن الله ما اعمى ابصارهم بيدهم الانجيل يقرونه ولا يفهموه انما مثلهم
  كمثل الحمار يحمل اسفارا اصدق الله العظيم ورسول الكريم}

  The expression ``ka-mathal al-ḥimār yaḥmilu asfāran'' is well known by
  Muslims, as it is found in Qur. 62:5 and used by Arabic grammarians as
  an illustrative case study.} but the basic idea is the same in the Arabic
original and the Aljamiado adaptation.

Christians are
compared to emph{goim} and are also accused of heresy (emph{herejía}),
mainly because of their inability to understand revelation. They are
compared to donkeys (emph{ḥimār}): an ``asno ke lieba libros''
(``donkey that carries books'').footnote{Cardaillac (1972, 2:41),
  Madrid, National Library of Spain, Aljamiado 4944, f.~45f. Algiers,
  National Library of Algeria, Ar. 1557, p.~57, lines 7--8.

  begin{Arabic}

  فسجن الله ما اعمى ابصارهم بيدهم الانجيل يقرونه ولا يفهموه انما مثلهم
  كمثل الحمار يحمل اسفارا اصدق الله العظيم ورسول الكريم

  end{Arabic}

  The expression ``ka-mathal al-ḥimār yaḥmilu asfāran'' is well known by
  Muslims, as it is found in Qur. 62:5 and used by Arabic grammarians as
  an illustrative case study.} but the basic idea is the same in the Arabic
original and the Aljamiado adaptation.

end{document}

documentclass[a4paper]{scrartcl}
usepackage{fontspec}
defaultfontfeatures{Scale=MatchLowercase}
defaultfontfeatures[rmfamily]{Ligatures=TeX,Scale=1}
setmainfont{Noto Serif}
setsansfont{Noto Sans}
newfontfamilyarabicfont[Script=Arabic]{Amiri}
PassOptionsToPackage{extrafootnotefeatures}{bidi}
usepackage{polyglossia}
setmainlanguage{english}
setotherlanguage{arabic}
begin{document}
nullvfill
Christians are compared to emph{goim} and are also accused of heresy
(emph{herejía}), mainly because of their inability to understand revelation.
They are compared to donkeys (emph{ḥimār}): an ``asno ke lieba libros''
(``donkey that carries books'').footnote{Cardaillac (1972, 2:41), Madrid,
  National Library of Spain, Aljamiado 4944, f.~45f. Algiers, National Library
  of Algeria, Ar. 1557, p.~57, lines 7--8.

  textarabic{فسجن الله ما اعمى ابصارهم بيدهم الانجيل يقرونه ولا يفهموه انما
  مثلهم كمثل الحمار يحمل اسفارا اصدق الله العظيم ورسول الكريم}

  The expression ``ka-mathal al-ḥimār yaḥmilu asfāran'' is well known by
  Muslims, as it is found in Qur. 62:5 and used by Arabic grammarians as an
illustrative case study.} but the basic idea is the same in the Arabic
original and the Aljamiado adaptation.

Christians are compared to emph{goim} and are also accused of heresy
(emph{herejía}), mainly because of their inability to understand revelation.
They are compared to donkeys (emph{ḥimār}): an ``asno ke lieba libros''
(``donkey that carries books'').footnote{Cardaillac (1972, 2:41), Madrid,
  National Library of Spain, Aljamiado 4944, f.~45f. Algiers, National Library
  of Algeria, Ar. 1557, p.~57, lines 7--8.

  begin{Arabic}
  فسجن الله ما اعمى ابصارهم بيدهم الانجيل يقرونه ولا يفهموه انما مثلهم كمثل
  الحمار يحمل اسفارا اصدق الله العظيم ورسول الكريم
  end{Arabic}

  The expression ``ka-mathal al-ḥimār yaḥmilu asfāran'' is well known by
  Muslims, as it is found in Qur. 62:5 and used by Arabic grammarians as an
illustrative case study.} but the basic idea is the same in the Arabic
original and the Aljamiado adaptation.
end{document}