provide one "partial" field per entry in aggregated responses
For example, https://datasets-server.huggingface.co/size?dataset=c4 only provides a global `partial: true` field and the response does not explicit that the "train" split is partial, while the "test" one is complete.

Every entry in `configs` and `splits` should also include its own `partial` field, to be able to show this information in the viewer (selects)

- currently:
  <img width="1528" alt="Capture d’écran 2023-07-19 à 16 00 28" src="https://github.com/huggingface/datasets-server/assets/1676121/92d27982-0fa3-44f2-a73f-a0ae614da40c">
- ideally, something like:
  <img width="1529" alt="Capture d’écran 2023-07-19 à 16 01 39" src="https://github.com/huggingface/datasets-server/assets/1676121/c638af93-30de-4ab7-8fdd-389202d41c88">

Endpoints where we want these extra fields:

- /info, dataset-level
- /size, dataset-level
- /size, config-level

provide one "partial" field per entry in aggregated responses: For example, https://datasets-server.huggingface.co/size?dataset=c4 only provides a global `partial: true` field and the response does not explicit that the "train" split is partial, while the "test" one is complete.

Every entry in `configs` and `splits` should also include its own `partial` field, to be able to show this information in the viewer (selects)

- currently:
  <img width="1528" alt="Capture d’écran 2023-07-19 à 16 00 28" src="https://github.com/huggingface/datasets-server/assets/1676121/92d27982-0fa3-44f2-a73f-a0ae614da40c">
- ideally, something like:
  <img width="1529" alt="Capture d’écran 2023-07-19 à 16 01 39" src="https://github.com/huggingface/datasets-server/assets/1676121/c638af93-30de-4ab7-8fdd-389202d41c88">

Endpoints where we want these extra fields:

- /info, dataset-level
- /size, dataset-level
- /size, config-level
