fix(bash-v2): activeHelp length check syntax (#1762)
fix(bash-v2): activeHelp length check syntax (#1762)

```shell
$ set -u
$ foo=()
$ echo ${#foo}
bash: foo: unbound variable
echo ${#foo[*]}
0
```
The above shows that an empty array needs the suffix `[*]` when checking its length, or else it is considered unbound.
spf13/cobra