Use the list repository tags API and its pagination in getContainerRepositoryTags

Context 🌅

Rollout issue for feature flag: [Feature flag] Rollout of `use_repository_list_... (#426358 - closed)

Today, we have the epic: Use new container registry API for listing repo... (&10208 - closed) that aims to implement the usage of the new API to list repository tags. After the investigation in #403314 (closed), the list repository tags API endpoint will be updated in container-registry#1012 (closed), container-registry#1000 (closed), and container-registry#1008 (closed) to support the functionalities we need in listing registry tags in the Gitlab UI.

After the three issues in the Container Registry is done, #411265 (closed) then updates ContainerRegistry::GitlabApiClient#tags, the interface on the rails side to the /gitlab/v1/*, to support the additional parameters and return value of the list repository tags API endpoint.

In this issue, we then use the updated ContainerRegistry::GitlabApiClient#tags in the resolver for getContainerRepositoryTags.

We will be putting this change behind a feature flag to be able to gradually rollout the change.

Implementation Plan 🗺

A. Updating the resolve function

In Resolvers::ContainerRepositoryTagsResolver#resolve, we will have two flows:

1. When the feature flag is on and the Gitlab API is supported, we fetch a page from ContainerRegistry::GitlabApiClient#tags
2. Else, we follow the original behaviour

def resolve(sort:, **filters)
  if is_gitlab_com_and_feature_flag_on?
    # Send in the parameters and get a page from the list registry tags API endpoint
    ...
    Gitlab::graphql::ExternallyPaginatedArray.new(previous_cursor, next_cursor, *tags)
  else
    # current behaviour here
  end
end

As we see above, we will utilize Gitlab::graphql::ExternallyPaginatedArray to follow the pagination of the list repository tags API.

B. Getting a page from the list repository tags API

def get_tags_page(before: nil, last: nil, sort: nil, name: nil, page_size: 100)
  raise ArgumentError, 'not a migrated repository' unless migrated?
  raise ArgumentError, 'block not given' unless block

  page = gitlab_api_client.tags(self.path,
    page_size: page_size,
    before: before,
    last: last,
    sort: sort,
    name: name
  )

  return {} unless page&.key?(:response_body)

  # return value here is still up for discussion, please see the Cursors section below
  {
    tags: transform_tags_page(page[:response_body]),
    previous_cursor: # get from page link header, 
    next_cursor: # get from page link header, 
  }
end

previous_cursor and next_cursor can be fetched from the updates that will be added in container-registry#1012 (closed).

This issue can be reviewed and updated further once the container registry issues are closed 😊