Boards - Remove List model from GraphQL boards [RUN AS-IF-FOSS]

What does this MR do?

Remove use of List model for Swimlanes and GraphQL boards.

Feature flag :graphql_board_lists is required to test GraphQL boards, only on Groups.

Affected pages to test

• Group Issue boards (/groups/gitlab-org/-/boards)
• Swimlanes on Group and Project boards (On a board, select Group By Epic in the top right dropdown)

Notable changes

Removing the use of List model requires to change a few attribute uses, so components only rely on attributes provided by GraphQL queries. Here is a short description of the main attributes changes:

• list.isExpandable is no longer needed. Only blank and promotion lists were not expandable and they have recently been removed.
• list.isExpanded -> !list.collapsed
• list.type -> list.listType
• list.issuesSize -> list.issueCount
• list.preset is not used anymore. blank and promotion being removed, we now test for backlog and closed list types instead.
• list.loadingMore is replaced with a flag on VueX state
• list.assignee.path -> list.assignee.webUrl

Soon to be deprecated REST boards are still using List model. Components with _new suffix are specific to GraphQL boards and do not rely on List model. When components are not split as such for REST and GraphQL boards, they support both List model and simple GraphQL lists.

Screenshots (strongly suggested)

No visual changes

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #290120 (closed)