[MINOR] Fix issue with failure penalty in multiagent env

[Mark2000]

Description

Fix an issue with failure penalties in the PettingZoo environment when the rewarder does not return a reward for a satellite.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

How should this pull request be reviewed?

• By commit
• All changes at once

How Has This Been Tested?

Added test to cover this case.

Future Work

None.

Checklist

• I have performed a self-review of my code
• I have commented my code in hard-to-understand areas
• I have made corresponding changes to the documentation and release notes
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works

[Copilot]

Pull Request Overview

This pull request addresses a bug where failure penalties were not correctly applied in the PettingZoo multiagent environment when the rewarder omitted a reward for a satellite. Key changes include the addition of a new unit test to cover this edge case, modifications in the _get_reward method to correctly apply penalties, and an update to the release notes documenting the fix.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tests/unittest/test_gym_env.py	Added a test case (test_get_reward_missing_sat) for the failure penalty logic.
src/bsk_rl/gym.py	Adjusted the _get_reward logic and added a debug print statement.
docs/source/release_notes.rst	Updated release notes to include the bug fix.

[LorenzzoQM]

Looks good.