Standardize executable empty blocks on pass

[andystaples]

Summary

• replace executable ellipsis-only bodies with explicit pass statements
• retain ... for typing-only @overload and Protocol declarations
• align abstract methods and test placeholders with the repository standard

Testing

• 292 targeted tests passed (7 skipped)
• flake8 passed for all changed files

[Copilot]

Pull request overview

This PR standardizes how executable-but-empty blocks are represented across the repo by replacing ellipsis-only (...) statement bodies with explicit pass, while preserving ... for typing-only constructs (e.g., @overload, Protocol).

Changes:

• Replaced ellipsis-only executable function bodies in tests with pass to match the repo’s established pattern for empty executable blocks.
• Updated abstract method bodies in core SDK and providers to use pass consistently.
• Kept typing-focused usage of ... out of executable contexts (per the PR intent).

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/durabletask/test_type_discovery.py	Replaces placeholder ellipsis bodies in nested test functions/classes with pass (signature/type-discovery tests).
tests/durabletask/test_orchestration_executor.py	Updates annotated test activity placeholders from ... to pass.
durabletask/serialization.py	Uses pass for DataConverter abstract method bodies to align with existing ABC usage patterns in the SDK.
durabletask/payload/store.py	Uses pass for PayloadStore abstract method bodies for consistency and clearer “empty executable block” intent.
azure-functions-durable/azure/durable_functions/internal/compat/token_source.py	Updates TokenSource.to_json() abstract method body to pass to match standardized style.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

[berndverst]

Reviewed the complete diff at f3818a5. The ellipsis-to-pass substitutions preserve signatures, abstractness, coroutine behavior, and runtime semantics, and the remaining executable ellipses are limited to overload or Protocol declarations. No actionable issues found.