[Error] Running `create` with `-a ""` hangs indefinitely

**Describe the bug**
- Running `distrobox create --name archlinux --additional-flags "" --image archlinux:latest` hangs indefinitely, but the same command without the `--additional-flags` flag works.

**To Reproduce**
1. Run `distrobox create --name archlinux --additional-flags "" --image archlinux:latest` and wait, and keep waiting.
2. Notice that the command does not run, and terminate it.
3. Run `distrobox create --name archlinux --image archlinux:latest`. It runs near instantly.

**Expected behavior**
The existence of `--additional-flags ""` should not affect the time required to create a container.

**Logs**
```
$ distrobox create --name archlinux --image archlinux:latest --verbose
+ '[' -z '' ']'
+ '[' -z archlinux:latest ']'
+ '[' -z archlinux ']'
+ '[' -z archlinux ']'
+ '[' -z '' ']'
++ uname -n
+ container_hostname=fedora
+ '[' 0 -eq 1 ']'
++ printf %s fedora
++ wc -m
+ '[' 6 -gt 64 ']'
+ case "${container_manager}" in
+ command -v podman
+ container_manager=podman
+ command -v podman
+ '[' 1 -ne 0 ']'
+ container_manager='podman --log-level debug'
+ '[' 0 -ne 0 ']'
+ '[' 0 -ne 0 ']'
+ '[' -n '' ']'
+ '[' -z /usr/bin/distrobox-init ']'
+ '[' -z /usr/bin/distrobox-export ']'
+ '[' 0 -ne 0 ']'
+ podman --log-level debug inspect --type container archlinux
+ printf 'Distrobox named '\''%s'\'' already exists.\n' archlinux
Distrobox named 'archlinux' already exists.
+ printf 'To enter, run:\n\n'
To enter, run:

+ '[' 0 -eq 1 ']'
+ '[' 1000 -eq 0 ']'
+ '[' 0 -eq 0 ']'
+ printf 'distrobox enter %s\n\n' archlinux
distrobox enter archlinux

+ exit 0
```
**Note:** The command with `--additional-flags "" --verbose` produces no logs.

**Desktop (please complete the following information):**

- Are you using podman, docker or lilipod? podman
- Which version or podman, docker or lilipod? podman version 5.7.1
- Which version of distrobox? distrobox: 1.8.2.2
- Which host distribution? Fedora Linux 43, Kernel 6.17.13-200.fc42.x86_64 (64-bit)
- How did you install distrobox? Using the `dnf` package manager

**Additional context**
I am getting a separate error if I put any actual flags inside `--additional-flags ""`, like `--gpus all`.

Examine o script distrobox create para ver como --additional-flags é analisado. O problema provavelmente ocorre quando uma string vazia é passada. Comece procurando por 'additional-flags' na base de código e, em seguida, acompanhe o fluxo para ver onde o travamento ocorre. Faça um teste com um echo simples ou uma instrução de depuração para confirmar o local do travamento. A correção deve garantir que flags vazias sejam tratadas corretamente sem afetar o tempo de criação do container.

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