Added export of connection basic metrics

[vladvildanov]

Description of change

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[Copilot]

Pull request overview

This pull request adds export of connection basic metrics to the Redis client by refactoring the connection count metric from an UpDownCounter to an Observable Gauge and implementing an event-based system for collecting connection lifecycle metrics.

Key Changes

• Refactored connection count metric from UpDownCounter to Observable Gauge with callback-based collection
• Added event dispatching for connection lifecycle events (created, timeout relaxed, handoff)
• Integrated event listeners to export metrics for maintenance notifications and connection operations
• Updated error type formatting to include "other:" prefix for better categorization

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
redis/observability/recorder.py	Replaced record_connection_count with init_connection_count using callback pattern; updated parameter names
redis/observability/metrics.py	Changed connection count from UpDownCounter to Observable Gauge; updated parameter names
redis/observability/attributes.py	Added DB_CLIENT_CONNECTION_NAME attribute constant
redis/observability/providers.py	Added optional import handling for OpenTelemetry SDK
redis/event.py	Added new event classes and listener implementations for connection metrics
redis/connection.py	Added get_connection_count method and event dispatching in connection pools
redis/maint_notifications.py	Integrated event dispatcher and added event emission for maintenance operations
tests/test_observability/test_recorder.py	Updated mocks from create_gauge and removed record_connection_count tests
tests/test_observability/test_config.py	Removed unused telemetry option tests
tests/test_maint_notifications.py	Added comprehensive tests for event emission
tests/test_connection_pool.py	Added tests for connection creation event emission
tests/test_client.py	Added tests for connection count initialization

Comments suppressed due to low confidence (1)

redis/observability/recorder.py:109

• The docstring example on line 109 is outdated. It still shows a string pool name being passed, but the function signature has been changed to accept a connection_pool object. Update the example to reflect the new signature.

    Example:
        >>> start = time.monotonic()
        >>> # ... create connection ...
        >>> record_connection_create_time('ConnectionPool<localhost:6379>', time.monotonic() - start)

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[petyaslavova]

LGTM.