[typespec-next] Swagger BreakingChange error "AddedAdditionalProperties"

The swagger updates caused by https://github.com/Azure/typespec-azure/pull/3391 raised these errors in check `Swagger BreakingChange`:

Rule | Message
-- | --
❌ 1021 - AddedAdditionalProperties | The new version adds an 'additionalProperties' element.
New: inference/preview/2023-06-01-preview/generated.json#L794:11
Old: inference/preview/2023-06-01-preview/generated.json#L794:11
❌ 1021 - AddedAdditionalProperties | The new version adds an 'additionalProperties' element.
New: inference/preview/2023-07-01-preview/generated.json#L827:11
Old: inference/preview/2023-07-01-preview/generated.json#L827:11
❌ 1021 - AddedAdditionalProperties | The new version adds an 'additionalProperties' element.
New: inference/stable/2022-12-01/generated.json#L351:11
Old: inference/stable/2022-12-01/generated.json#L351:11
❌ 1021 - AddedAdditionalProperties | The new version adds an 'additionalProperties' element.
New: inference/stable/2023-05-15/generated.json#L592:11
Old: inference/stable/2023-05-15/generated.json#L592:11

https://github.com/Azure/azure-rest-api-specs/pull/25323/checks?check_run_id=15930722524

@timotheeguerin: Can you comment on this? If this is a valid breaking change to the swagger, what are the implications for merging this to main at the next TypeSpec release?

Start with the Swagger BreakingChange check and the changes from azure/typespec-azure#3391. Compare the listed generated.json locations for the 2023-06-01-preview, 2023-07-01-preview, 2022-12-01, and 2023-05-15 versions, then review azure-rest-api-specs#25323. Done means establishing whether the AddedAdditionalProperties findings are valid and recording the implications for merging.

Written by the indexing model from the issue text.