[Enhancement]: Container Exec not returning stderr, on multiplexed option

[gutocondela]

Testcontainers version

v0.26.0

Using the latest Testcontainers version?

Yes

Host OS

Linux

Host arch

X86

Go version

1.19

Docker version

Client: Docker Engine - Community
 Version:           24.0.7
 API version:       1.43
 Go version:        go1.20.10
 Git commit:        afdd53b
 Built:             Thu Oct 26 09:07:41 2023
 OS/Arch:           linux/amd64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          24.0.7
  API version:      1.43 (minimum version 1.12)
  Go version:       go1.20.10
  Git commit:       311b9ff
  Built:            Thu Oct 26 09:07:41 2023
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.6.25
  GitCommit:        d8f198a4ed8892c764191ef7b3b06d8a2eeb5c7f
 runc:
  Version:          1.1.10
  GitCommit:        v1.1.10-0-g18a0cb0
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Docker info

Client: Docker Engine - Community
 Version:    24.0.7
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.11.2
    Path:     /usr/libexec/docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.21.0
    Path:     /usr/libexec/docker/cli-plugins/docker-compose

Server:
 Containers: 174
  Running: 33
  Paused: 0
  Stopped: 141
 Images: 38
 Server Version: 24.0.7
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: d8f198a4ed8892c764191ef7b3b06d8a2eeb5c7f
 runc version: v1.1.10-0-g18a0cb0
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.2.0-36-generic
 Operating System: Ubuntu 22.04.3 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 15.21GiB
 Name: gutocondela-virtual-machine
 ID: 3dddf620-58b0-419d-a514-2ab5fadd5d05
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Username: gutocondela
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

What happened?

When executing a command that should generate error, on a running container, it doens't return the stderr output.

Relevant log output

No response

Additional information

No response

[mdelapenya]

I'm changing the labels, so that we are adding a new capability, which is returning stderr on failures.