conformance: remove try-except blocks from server impl

[tsubakiky]

This pull request primarily focuses on simplifying error handling in the conformance/server.py file by removing redundant try-except blocks, alongside a few other minor updates to improve maintainability and clean up unused configurations.

Error handling simplification in conformance/server.py:

• Removed redundant try-except blocks for ConnectError and generic exceptions in multiple asynchronous methods, including Unary, IdempotentUnary, ClientStream, ServerStream, and BidiStream. This change assumes that unhandled exceptions will propagate naturally, simplifying the code and reducing unnecessary boilerplate. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

Configuration and logging cleanup:

• Removed the duplicate metadata test case entry from conformance/run-testcase.txt to avoid redundancy.
• Removed the unused "Deadline Propagation" configuration from conformance/server_known_failing.yaml.
• Refactored logging setup in conformance/server_runner.py to streamline logger initialization and ensure consistent logging behavior.