FND-3847: add pyatlan_v9 creators for the 3 Cosmos MongoDB types

[cmgrote]

✨ Description

Adds creator() for the 3 Cosmos MongoDB asset types in pyatlan_v9: CosmosMongoDBAccount, CosmosMongoDBDatabase, CosmosMongoDBCollection. Both atlan-cosmosdb-app and atlan-cosmosnosql-app emit these types with the same qualifiedName shape, so one creator per type fits both.

CosmosMongoDBCollection.creator(
    name="line_items",
    cosmos_mongo_db_database_qualified_name="default/cosmos/1712345678/accounts/sales-account/databases/orders",
)
# qualified_name == "default/cosmos/1712345678/accounts/sales-account/databases/orders/collections/line_items"

• Exact app parity: {conn}/accounts/{account}, .../databases/{db}, .../collections/{collection}, the strings both apps emit today (FND-3838 census). A different string would re-key existing assets.
• Parent relationship and denormalised attributes are set: Database sets cosmosMongoDBAccount + cosmosMongoDBAccountQualifiedName; Collection sets cosmosMongoDBDatabase + cosmosMongoDBDatabaseQualifiedName + databaseName / databaseQualifiedName (inherited from Table, and set by both apps). validate(for_creation=True) passes with no extra checks in the overlay.
• connection_qualified_name is optional on Database / Collection; when omitted it is the first 3 segments of the parent qualifiedName (a too-short parent QN raises).
• Blank inputs raise (validate_required_fields).
• Parent inputs are named after the typedef attributes, like the ADLS creators.
• Overlays in pyatlan_v9/model/assets/_overlays/cosmos_mongo_db_*.py; the 3 classes are regenerated from atlanhq/models with these overlays (pkl sdkOnly=python + pre-commit, the same steps as sync-python-sdk.yaml).

Linear: FND-3847 — required-attributes analysis table is in the issue comments.
Paired models PR (merge first): https://github.com/atlanhq/models/pull/2081 — adds the matching qualifiedNameFormula, which drives the regenerated _QUALIFIED_NAME_PATTERN.

---

🧩 Type of change

• 🚀 New feature (non-breaking change that adds functionality)

---

✅ How has this been tested?

• tests_v9/unit/model/cosmos_mongo_db_test.py (26 tests): literal app qualifiedName per type, account → database → collection chaining, relationship + denormalised attributes, name pattern match, validate(for_creation=True), missing / blank / too-short inputs, create and create_for_modification aliases.
• Mutation check: changing the Collection slug collections → containers fails the parity tests.
• With the models PR branch, only the 3 Cosmos MongoDB classes change.
• pytest tests_v9/unit: 7701 passed, 5 skipped. pre-commit clean on all changed files.
• Not done: a production check that existing Cosmos MongoDB assets all match the stricter patterns (the Cognos PR did one). Both apps' transformers emit exactly these shapes.

---

🤖 Generated with Claude Code

https://claude.ai/code/session_011uG1w2Vm1KcdbnG1wpbCXc

[linear]

FND-3847