At the start of a session, check if the storage size is compatible with the repository

[leafty]

For legacy sessions, we can check if the repository size (+ LFS storage if applicable) fits inside the requested session storage.

Here are the relevant fields from the GitLab API:

{
  "statistics": {
    "repository_size": "<in bytes>",
    "lfs_objects_size": "<in bytes>",
  }
}