ci: reinstall libbrotli-dev on Linux test runners (#2391)
The Linux Caddy module tests fail at compile time:
```
../../../../go/pkg/mod/github.com/google/brotli/go/cbrotli@v1.1.0/reader.go:13:10: fatal error: brotli/decode.h: No such file or directory
```
`caddy/` pulls in
[`github.com/dunglas/caddy-cbrotli`](https://github.com/dunglas/caddy-cbrotli),
which depends on
[`github.com/google/brotli/go/cbrotli`](https://github.com/google/brotli/tree/master/go/cbrotli)
and uses ``// #cgo pkg-config: libbrotlicommon libbrotlidec
libbrotlienc``.
## Root cause
The `ubuntu-latest` runner (noble, image `ubuntu24/2026..*`) lists
`libbrotli-dev 1.1.0-2build2` as installed in dpkg, but the package's
files are missing on disk. Diagnostics from a CI run on this branch:
```
$ dpkg -l | grep brotli
ii brotli 1.1.0-2build2 amd64 ...
ii libbrotli-dev:amd64 1.1.0-2build2 amd64 ...
ii libbrotli1:amd64 1.1.0-2build2 amd64 ...
$ ls /usr/include/brotli/
ls: cannot access '/usr/include/brotli/': No such file or directory
$ find /usr -name 'libbrotli*.pc'
/usr/share/miniconda/lib/pkgconfig/libbrotli{common,dec,enc}.pc
# system /usr/lib/x86_64-linux-gnu/pkgconfig/libbrotli*.pc absent
$ pkg-config --cflags libbrotlicommon libbrotlidec libbrotlienc
Package libbrotlicommon was not found in the pkg-config search path.
Package 'libbrotlicommon', required by 'virtual:world', not found
```
A plain `apt-get install -y libbrotli-dev` is a no-op because dpkg
believes the package is current. `--reinstall` forces apt to re-extract
the files so cgo's pkg-config invocation succeeds and gcc can resolve
`<brotli/decode.h>`.
Reproduces on PR-2365
https://github.com/php/frankenphp/actions/runs/25315574252/job/74212221237
and on every recent main run, e.g.
https://github.com/php/frankenphp/actions/runs/25286789334.
---------
Signed-off-by: Kévin Dunglas <kevin@dunglas.fr>
