Improve discoverability of import results
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## User Problem
### Viewing results of direct transfer
When I import GitLab resources with direct transfer, when the process completes, I receive an email, which links to import results for this particular migration:

I receive an email when I import a top-level group from UI or just a single project with API.
When I click on the button "See results" in the email, I see the results for this particular migration process like this:

At this point I can review import results of this particular migration process, limited as it is, but I can.
However, I cannot easily access the import results of a specific top level group or a specific import process from the direct transfer history page/group history page. Direct transfer history page/group history page looks like this:

and lists all groups, subgroups and projects that I ever migrated with direct transfer (DT) into the destination instance I'm currently on.
Also, navigating to this page could be improved. Currently I can navigate there clicking at button on the page where I connect GL instances in preparation for DT:

Once I close the import results of a specific top level group or a specific import process page, I can access it again, but to do it I have to connect the instances first and navigate to it from a page that lists top-level groups that can be migrated, clicking on "Migration details" button:

Summing up:
1. Users are missing a link on the direct transfer history page to the Import Results Page for a given single migration (`/import/bulk_imports/#####/history`, e.g, https://gitlab.com/import/bulk_imports/2021477/history).
2. The current Direct Transfer History Page lists everything in one, long, un-searchable or filterable list.
3. Only user that initiated migration is informed by email that migration completed and not all destination group Owners - there's another issue for it: https://gitlab.com/gitlab-org/gitlab/-/issues/441403+
#### Particularities when importing a project with DT via API
When I import project with DT via API I receive an email upon import completion, as written above and I can see the imported project listed on the project history page:

and on the group history page as well:

Dates are inconsistent and the status on the project history page is wrong (says "Not started"), but it's the same imported project.
#### Possible solution
The "top level" group migration history page (https://gitlab.com/import/bulk_imports/history) could list single/separate migrations (each has migration ID).
In a single migration process there could be multiple sources and destinations (source group/project, destination group/project), so we won't show those columns here. After https://gitlab.com/gitlab-org/gitlab/-/issues/462998+ is done, we can show also `Source hostname` column on this page:

In further iteration we can add a counter cache to store how many groups / projects were discovered for import and display the extra stats - number of groups and projects imported in single migration.
When a user clicks on `Migration details` link, they arrive to `/import/bulk_imports/<ID>/history` which lists all groups and projects within single import.
- [UX Flow](https://gitlab.com/gitlab-org/gitlab/-/issues/431178/designs/Improve_discoverability_of_import_results_-_Flow.png)
- [Figma File](https://www.figma.com/design/61VAq2Td19GKkGNJoy31eT/Improve-discoverability-of-import-results?node-id=4%3A1381&t=iSJj7ItDJGYWzVxY-1)
Another option: Rethink the general structure - if we removed the separation for group and project imports, we could have one entry point and one import history page.
### Questions
1. For future iteration: I wonder if and where else we could add a link to imported groups and project? Perhaps on https://gitlab.com/dashboard/groups??
2. Should we add the link to the direct transfer history page from the project import history page?
issue