Not selecting an embed makes query blow up

**Describe the bug**
If you don't select the embed, the query blows up.

**To Reproduce**
```
iex(5)> Safari.Virtual.CesiumAsset |> Ash.Query.select(:id) |> Ash.stream!() |> Stream.run()
[debug] QUERY OK source="cesium_assets" db=4.3ms queue=0.1ms idle=1937.1ms
SELECT c0."id" FROM "cesium_assets" AS c0 ORDER BY c0."id" LIMIT $1 [251]
↳ anonymous fn/3 in AshPostgres.DataLayer.run_query/2, at: lib/data_layer.ex:749
** (KeyError) key :__metadata__ not found in: #Ash.NotLoaded<:attribute, field: :cesium_bucket_credentials>
(ash 3.0.7) lib/ash.ex:1703: Ash.load/3
(ash 3.0.7) lib/ash/type/type.ex:1216: anonymous fn/2 in Ash.Type.splicing_nil_values/2
(ash 3.0.7) lib/ash/actions/read/read.ex:1349: anonymous fn/7 in Ash.Actions.Read.load_through_attributes/7
(elixir 1.16.3) lib/enum.ex:4839: Enumerable.List.reduce/3
(elixir 1.16.3) lib/enum.ex:2582: Enum.reduce_while/3
(ash 3.0.7) lib/ash/actions/read/read.ex:1301: anonymous fn/8 in Ash.Actions.Read.load_through_attributes/7
(elixir 1.16.3) lib/enum.ex:4839: Enumerable.List.reduce/3
(elixir 1.16.3) lib/enum.ex:2582: Enum.reduce_while/3
(ash 3.0.7) lib/ash/actions/read/read.ex:259: Ash.Actions.Read.do_run/3
(ash 3.0.7) lib/ash/actions/read/read.ex:66: anonymous fn/3 in Ash.Actions.Read.run/3
(ash 3.0.7) lib/ash/actions/read/read.ex:65: Ash.Actions.Read.run/3
(ash 3.0.7) lib/ash.ex:1845: Ash.read/2
(ash 3.0.7) lib/ash.ex:1804: Ash.read!/2
(ash 3.0.7) lib/ash/actions/read/stream.ex:45: anonymous fn/5 in Ash.Actions.Read.Stream.do_stream/4
(elixir 1.16.3) lib/stream.ex:1626: Stream.do_resource/5
(elixir 1.16.3) lib/stream.ex:690: Stream.run/1
iex:5: (file)
```

**Expected behavior**
Thing not go boom and I can select only ID

**Runtime**
- `"ash": {:hex, :ash, "3.0.7", "6c37e092f53b1b21eb89596f600a652b2a601f84378f44fd5dd1cdec72eb1cc2"`

**Additional context**
Add any other context about the problem here.

Run the provided IEx reproduction and start with lib/data_layer.ex:749, then trace the failure through lib/ash/actions/read/read.ex and lib/ash.ex. Done means Ash.stream! with Ash.Query.select(:id) completes without the KeyError when the embed is not selected.

Written by the indexing model from the issue text.