Support query for multiple groups

What does this MR do?

We should support a todo query for multiple groups:

{
  currentuser {
    todos(group_id: [387, 29839, 775]) {
      nodes {
        body
        id
        state
        action
        targetType
      }
    }
  }
}

This MR also adds the possibility to override the default TodosFinder handling / query for either done or pending todos by providing explicit_state_query to the params hash.

#31914 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

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

#31914 (closed)