Support image tag property in `lambda package-ci` command

`-it | --image-tag` looks like it is supported in `package` but not `package-ci`. Is this as designed?

https://github.com/aws/aws-extensions-for-dotnet-cli/blob/9639f8f4902349d289491b290979a3a1671cc0a5/src/Amazon.Lambda.Tools/Commands/PackageCommand.cs#L31

https://github.com/aws/aws-extensions-for-dotnet-cli/blob/9639f8f4902349d289491b290979a3a1671cc0a5/src/Amazon.Lambda.Tools/Commands/PackageCICommand.cs#L26-L37

## Describe the Feature

Allowing users to specify the tag for my Docker image using the `--image-tag` switch.

### Is your Feature Request related to a problem?

The generated image tag (taken from the project name) might not be the one that's desired.

## Proposed Solution

Unsure. Is this code base up to date with what is published as a dotnet tool?

### Describe alternatives you've considered

Accepting life as-is.
Edit: It appears to work when set in `aws-lambda-tools.defaults.json`.

## Additional Context

### Environment

* [ ] :wave: I may be able to implement this feature request
* [ ] :warning: This feature might incur a breaking change

---

This is a :rocket: Feature Request

Start by comparing the option handling in src/Amazon.Lambda.Tools/Commands/PackageCommand.cs with src/Amazon.Lambda.Tools/Commands/PackageCICommand.cs, especially the referenced sections. Trace how package-ci builds its Docker image configuration and verify that --image-tag is accepted and controls the generated image tag consistently with package.

Written by the indexing model from the issue text.