[BUG] `git reset --hard` fails with `update = none` submodules

# What did you do before the bug happened? (Steps to reproduce your issue)
1. Clone a git repository that sets `update = none` in .gitmodules:
$ git clone --recurse-submodules https://github.com/ubolonton/tree-sitter-langs

2. Perform a hard reset:
$ cd tree-sitter-langs
$ git reset --hard

# What did you expect to happen? (Expected behavior)
The reset should succeed and do nothing.

# What happened instead? (Actual behavior)
The reset command fails with

fatal: not a git repository: ../../.git/modules/repos/agda
fatal: could not reset submodule index

[System Info]
git version:
git version 2.32.0
cpu: x86_64
no commit associated with this build
sizeof-long: 8
sizeof-size_t: 8
shell-path: /bin/sh
uname: Linux 5.12.10-hardened1-1-hardened #1 SMP PREEMPT Thu, 10 Jun
2021 21:12:42 +0000 x86_64
compiler info: gnuc: 11.1
libc info: glibc: 2.33
$SHELL (typically, interactive shell): /usr/bin/zsh