Fetching upstream remote fails if repo was a blobless clone

[Justin Su <injustsu@gmail.com>]

Thank you for filling out a Git bug report!
Please answer the following questions to help us understand your issue.

What did you do before the bug happened? (Steps to reproduce your issue)

```
git clone --filter=blob:none git@github.com:injust/delta
cd delta/
git remote add upstream git@github.com:dandavison/delta
git fetch upstream
```

What did you expect to happen? (Expected behavior) Fetch the upstream repo

What happened instead? (Actual behavior)

```
remote: Enumerating objects: 1578, done.
remote: Counting objects: 100% (776/776), done.
remote: Compressing objects: 100% (15/15), done.
remote: Total 1578 (delta 772), reused 761 (delta 761), pack-reused 802 (from 2)
Receiving objects: 100% (1578/1578), 2.67 MiB | 5.34 MiB/s, done.
Resolving deltas: 100% (1156/1156), completed with 356 local objects.
fatal: did not receive expected object 0020d54b979cc8cf59a13406f98bfe515b190559
fatal: fetch-pack: invalid index-pack output
```

Anything else you want to add: This only happens if a blobless clone
is performed


[System Info]
git version:
git version 2.50.1
cpu: x86_64
no commit associated with this build
sizeof-long: 8
sizeof-size_t: 8
shell-path: /bin/sh
feature: fsmonitor--daemon
libcurl: 8.6.0
zlib: 1.2.12
SHA-1: SHA1_DC
SHA-256: SHA256_BLK
uname: Darwin 24.5.0 Darwin Kernel Version 24.5.0: Tue Apr 22 19:53:26
PDT 2025; root:xnu-11417.121.6~2/RELEASE_X86_64 x86_64
compiler info: clang: 16.0.0 (clang-1600.0.26.6)
libc info: no libc information available
$SHELL (typically, interactive shell): /usr/local/bin/fish