Notes on the 'dandi' and 'DANDI' contexts.

didn't check if name spaces even case sensitive etc, but while conversions from/to/between linkml and pydantic models we get

```
WARNING:linkml_runtime.Namespaces:dandi namespace is already mapped to Prefix({'prefix_prefix': 'DANDI', 'prefix_reference': 'http://dandiarchive.org/dandiset/'}) - Overriding with mapping to Prefix({'prefix_prefix': 'dandi', 'prefix_reference': 'http://schema.dandiarchive.org/'})
```

which stems from us originally defining both `DANDI` and `dandi` prefixes in [context.json](https://github.com/dandi/schema/blob/master/releases/0.7.0/context.json#L7) . Likely the `DANDI` prefix could be used as [id_prefiexes](https://linkml.io/linkml/faq/modeling.html#what-are-id-prefixes-used-for) for instances of `Dandisets` thus kinda making it a legitimate case. But then we need to figure out why linkml maps both 'dandi' and 'DANDI' into the same namespace.

First we thought to remove it but feels like potentially a legit case to check more in detail.

Note that in jsonschema I do not think we use DANDI at all:

```
❯ grep DANDI *
asset.json: "description": "Licenses associated with the item. DANDI only supports a subset of Creative Commons Licenses (creativecommons.org) applicable to datasets.",
context.json: "DANDI": "http://dandiarchive.org/dandiset/",
dandiset.json: "description": "A body of structured information describing a DANDI dataset.",
dandiset.json: "description": "Licenses associated with the item. DANDI only supports a subset of Creative Commons Licenses (creativecommons.org) applicable to datasets.",
published-asset.json: "description": "Licenses associated with the item. DANDI only supports a subset of Creative Commons Licenses (creativecommons.org) applicable to datasets.",
published-dandiset.json: "description": "Licenses associated with the item. DANDI only supports a subset of Creative Commons Licenses (creativecommons.org) applicable to datasets.",
```

so it could be potentially kicked out from there but likely we do still want it for LinkML version of the schema