Refactor personal access components out of vue_shared folder

What does this MR do and why?

On the logged-in user -> User settings -> Personal access tokens page, a table of created tokens is shown. We are redesigning this table behind a WIP feature flag:

In previous MRs, the redesigned table was added to the vue_shared folder to keep it close to the component that uses it. However, this redesigned table is only used by the personal access tokens folder, so it does not belong in vue_shared. This MR moves it to a new personal_access_tokens folder and makes the following changes:

1. The component that showed the new table (~/vue_shared/access_tokens/components/access_tokens.vue) was previously toggling between the new and old table based on the feature flag. It has been reworked to have a slot instead of directly rendering the table.

2. ~/personal_access_tokens/components/tokens_app.vue and ee/service_accounts/components/access_tokens_app.vue were created to pass the correct table to the new slot. Service account access tokens still needs to show the old table, only personal access tokens should show the new table.

How to set up and validate locally

Start with the fine_grained_personal_access_tokens feature flag disabled, then follow this video guide:

2025-11-11_01-00-42

Related to #570705 (closed)