Container doesn't start because user.Current() fails inside the entry point

**Describe the bug**
When trying to enter the container `fedora-toolbox-35` created using
```shell
toolbox create --distro fedora --release 35
```
I get the error
```shell
$ toolbox enter fedora-toolbox-35
Error: invalid entry point PID of container fedora-toolbox-35
```
To have a better error message I tried to attach to the container using `podman` instead of `toolbox` and got the error:
```shell
$ podman start --attach --interactive fedora-toolbox-35
Error: failed to get the current user: user: lookup userid 0: invalid argument
```
This error is returned by `toolbox` whenever Golang's `user.Current()` [gets an error when calling `getpwuid_r`](https://github.com/containers/toolbox/blob/73c53a347b402748b6a12ef9f74cecb7e8528c38/src/cmd/root.go#L316).

**Steps how to reproduce the behaviour**
1. toolbox create --distro fedora --release 35
2. toolbox enter fedora-toolbox-35

**Expected behaviour**
toolbox should start the default user shell inside a container.

**Actual behaviour**
toolbox exits with error code `1` and prints the error `Error: invalid entry point PID of container fedora-toolbox-35`.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Output of `toolbox --version` (v0.0.90+)**
```
toolbox version 0.0.99.3
```
**Toolbox package info (`rpm -q toolbox`)**
```
toolbox-0.0.99.3-2.fc34.x86_64
```
**Output of `podman version`**
```
Version: 3.4.2
API Version: 3.4.2
Go Version: go1.16.8
Built: Sun Nov 14 00:16:48 2021
OS/Arch: linux/amd64
```

**Podman package info (`rpm -q podman`)**
```
podman-3.4.2-1.fc34.x86_64
```

**Info about your OS**
Fedora Silverblue 34

**Additional context**
Add any other context about the problem here.
When did the issue start occurring? After an update (what packages were updated)?
If the issue is about operating with containers/images (creating, using, deleting,..), share here what image you used. If you're unsure, share here the output of `toolbox list -i` (shows all toolbox images on your system).
```
IMAGE ID IMAGE NAME CREATED
ab8bc106d4a7 2 months ago
d8a734db8c5c registry.fedoraproject.org/fedora-toolbox:34 7 months ago
40b181c70b73 registry.fedoraproject.org/fedora-toolbox:35 4 weeks ago
```

If you see an error message saying: `Error: invalid entry point PID of container `, add to the ticket output of command `podman start --attach `.

Start by reproducing the failure with `toolbox create --distro fedora --release 35` and `toolbox enter fedora-toolbox-35`, then inspect `src/cmd/root.go` around the `user.Current()` call. Compare the toolbox and Podman errors and trace the entry-point handling. Done means the Fedora toolbox starts the default user shell instead of exiting with the invalid entry point error.

Written by the indexing model from the issue text.