Fetch only ongoing dispatches

[Marenz]

Based on frequenz-floss/frequenz-client-dispatch-python#212

[Copilot]

Pull Request Overview

This PR optimizes the dispatch fetching functionality by filtering out completed dispatches, fetching only ongoing ones to improve performance and relevance.

• Adds an end_from parameter to the dispatch client API call to filter out past dispatches
• Updates tests to handle the new behavior where finished dispatches are filtered out
• Temporarily uses a development version of the frequenz-client-dispatch dependency

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
src/frequenz/dispatch/_bg_service.py	Adds time-based filtering to only fetch ongoing dispatches using end_from parameter
tests/test_frequenz_dispatch.py	Updates test expectations and adds logging to handle the new filtering behavior
pyproject.toml	Temporarily switches to development branch of frequenz-client-dispatch dependency
RELEASE_NOTES.md	Documents the new optimization feature

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[Copilot]

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

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[llucax]

Nice, LGTM, no approving only because of the PR dependency.