Remove trailing empty argument in ContainerCommand

[ssemyan]

The New-AzContainerGroup -Command argument adds an extra empty argument to the end of the commands. This is because Parser.ParseInput will return EOF as the final token. This means any programs using command arguments will get an extra empty argument passed in. The Python-based az cli does not do this. To repro:

1. Create an app that shows how many arguments were passed into it. For example in .net core:

class Program
{
        static void Main(string[] args)
        {
            Console.WriteLine("I have {0} arguments", args.Length);
        }
}

2. Add this to a container and push to a registry.
3. Run the container as an ACI using powershell

New-AzContainerGroup -ResourceGroupName test -Name bugtest -Image showargImage -OsType Linux -Command "dotnet showargs.dll one two three"

4. Examine the logs:

Get-AzContainerInstanceLog -ResourceGroupName test -ContainerGroupName bugtest
I have 4 arguments

5. Run the image using the az CLI

az container create --resource-group test --name bugtest2 --image showargImage --command-line "dotnet BugTest.dll one two three"

6. Examine the output

az container logs --resource-group akstest --name bugtest2
I have 3 arguments

Description

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate change log has been updated
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • the changes have gone through a cmdlet design review (Microsoft internal partners only)
  • the cmdlet markdown files were generated using the platyPS module

[markcowl]

Thanks for the contribution - if you can add a short description for this change to the changelog, we will be happy to include it.

Comment addressed