feat(provider/azure): Add Power BI triggers, operators and tests for dataset and workspace operations

[mvfc]

Description

This PR introduces deferrable versions of the Power BI workspace- and dataset-list operators in the Azure provider package. Instead of blocking a worker slot while calling the Power BI REST API, these operators now:

• Defer execution using custom BaseTrigger implementations
• Poll asynchronously for the full list of workspaces or datasets
• Resume execution once data is available and push IDs into XCom

New Hook methods

• PowerBIHook.get_workspace_list()
• PowerBIHook.get_dataset_list(group_id: str)

New Trigger classes

• PowerBIWorkspaceListTrigger
• PowerBIDatasetListTrigger

New Operator classes

• PowerBIWorkspaceListOperator
• PowerBIDatasetListOperator

Unit tests

• Trigger serialization (serialize())
• Trigger run logic (success and error paths)
• Operator deferral (TaskDeferred)
• Operator resume handling (execute_complete)
• XCom key/value assertions

Motivation and Context

Long-running or paginated API calls can occupy a worker slot for tens of seconds or more, limiting concurrency and throughput. By deferring:

1. We free up the worker while waiting on Power BI.
2. We align with Airflow’s best practices for asynchronous I/O.
3. We make scaling in high-volume environments more efficient.

This change complements existing synchronous operators; it does not remove or alter any blocking behavior, giving users the choice.

How Has This Been Tested?

• 🧪 Automated tests under tests/providers/microsoft/azure/ covering all new code paths.
• 🔄 Manual end-to-end DAG against a real Power BI service principal.
• ✅ Verified that XCom payloads contain the correct ID lists on resume.
• ✅ Verified appropriate error handling and retries in failure cases.

Documentation

• Added howto/operator:PowerBIWorkspaceListOperator and howto/operator:PowerBIDatasetListOperator pages.
• Updated Azure provider README to mention the new deferrable operators.

Backwards-Incompatible Changes?

No. Existing synchronous PowerBIHook methods and operators remain unchanged and fully supported.

New Dependencies?

None. All new code relies on existing Airflow and Azure provider infrastructure.

[mvfc]

ok i redid the rebase locally and pushed it again, sadly that closed the last PR @jscheffl but thanks for pointing it out, not sure what went wrong there

[potiuk]

cc: @ambika-garg -> can you take a look please ?

[ambika-garg]

reviewed the code, it looks good to me. Let me know if you'd like me to review anything specific.

[mvfc]

fixed the db test issues, was passing an extra argument that i removed from the examples in system tests

[gopidesupavan]

@mvfc overall LGTM, few nits.

[mvfc]

@mvfc overall LGTM, few nits.

thanks for the review and comments, will resolve asap :-)

[mvfc]

all resolved, all tests passed

[jscheffl]

@ambika-garg uff there had been many changes, can you re-review? I am not an expert but before merge would like to have some expert view on this. Due to re-base I can not see the DIFF to before :-(

[mvfc]

@jscheffl

@ambika-garg uff there had been many changes, can you re-review? I am not an expert but before merge would like to have some expert view on this. Due to re-base I can not see the DIFF to before :-(

my bad, still new and getting used to this rebase thing

[gopidesupavan]

Just two nits, rest LGTM.

[gopidesupavan]

Good work, thanks for the changes.

[mvfc]

Good work, thanks for the changes.

Thanks. Thanks for the help and sharp eye.