Update ChannelManager.kt

[lukisk]

Closes #636

Description

The cancellation exception on upstream channel does not cause the closure of all other channels.

Type of Change

• [x] 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)
• [ ] This change requires a documentation update

Test Plan

How has this been tested? Please describe the tests that you added to verify your changes.

Checklist:

Before submitting your PR, please review and check all of the following:

• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my change is effective
• [x] New and existing unit tests pass locally with my changes

Additional Notes:

The cancellation exception from the upstream channel was caught in the StoreActor while handling messages. This caused the closure of the actor.

[digitalbuddha]

Good catch! Do you mind adding a test to prove the functionality?

[lukisk]

yes, i will do it

[lukisk]

@digitalbuddha please, can you check it?