Error: unknown flag: --unitname

### Error: unknown flag: --unitname

When using `goal asset send` with the `--creator` and `--asset` arguments (I'm aware I could use `--assetid`, I'm just playing around) I'm met with the warning about `--asset` being deprecated and that I should use `--unitname` instead.

`Warning: The [--asset] flag is deprecated and will be removed in a future release, use [--unitname] instead.`

But when do that I get an error saying `--unitname` doesn't exist.

`Error: unknown flag: --unitname`

### Your environment

8590196737
2.4.1.stable [rel/stable] (commit #573a34c4)
go-algorand is licensed with AGPLv3.0
source code available at https://github.com/algorand/go-algorand

This is inside the sandbox environment on a Linux Mint system.

### Steps to reproduce

1. `goal asset create --creator --decimals 0 --total 1 --name "Test Asset" --unitname TA`
2. `goal asset send --assetid 1 -a 0 -f -t ` (use the assetid from above.)
3. `goal asset send -a 1 --creator --asset TA -f -t `
Warning: The [--asset] flag is deprecated and will be removed in a future release, use [--unitname] instead.
4. `goal asset send -a 1 --creator --unitname TA -f -t `
Error: unknown flag: --unitname

### Expected behaviour

I'd expect `--unitname` to be available after being told to use it over `--asset`.

### Actual behaviour

I'm told `--unitname` isn't available.