Add aio extras to azure-cosmos for async dependencies (#47143)

* Initial plan

* Add `aio` extras_require to azure-cosmos for async dependencies

Adds an optional `aio` dependency extra to the azure-cosmos package
so users can install async dependencies (aiohttp via azure-core[aio])
with `pip install azure-cosmos[aio]`. This follows the same pattern
used by other Azure SDK packages like azure-storage-queue.

Fixes #39457

Co-authored-by: simorenoh <30335873+simorenoh@users.noreply.github.com>

* Apply suggestion from @simorenoh

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: simorenoh <30335873+simorenoh@users.noreply.github.com>

Author: Copilot

sdk/cosmos/azure-cosmos/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 #### Features Added
 * Added **preview** support for the optional `embeddingSource` field on entries in `vector_embedding_policy.vectorEmbeddings`, which allows the service to generate vector embeddings from the specified item paths. Requires the embedding-generation service to be enabled on the account. See [46870](https://github.com/Azure/azure-sdk-for-python/pull/46870)
+* Added `aio` extras to the package, allowing users to install async dependencies with `pip install azure-cosmos[aio]`. See [PR 47143](https://github.com/Azure/azure-sdk-for-python/pull/47143)
 
 #### Breaking Changes
 * `CosmosItemPaged.get_response_headers()` and `CosmosAsyncItemPaged.get_response_headers()` now return a single `CaseInsensitiveDict` (the latest page) instead of `List[CaseInsensitiveDict]` (introduced in 4.16.0b1); `get_last_response_headers()` has been removed. This avoids unbounded memory growth on large queries. **Migration:** code that previously accessed `headers[i]['x-ms-request-charge']` should switch to `headers['x-ms-request-charge']` for the latest page, or pass `response_hook=` to the query method to receive per-page headers as they arrive. See [PR 47172](https://github.com/Azure/azure-sdk-for-python/pull/47172).

sdk/cosmos/azure-cosmos/setup.py

@@ -80,4 +80,9 @@
         "azure-core>=1.30.0",
         "typing-extensions>=4.6.0"
     ],
+    extras_require={
+        "aio": [
+            "azure-core[aio]>=1.30.0",
+        ],
+    },
 )