CELE-144 Fix synapses that are not removed after the deletion of a related Neuron

[aranega]

This closes the issue encoutered by @SimaoBolota-MetaCell for CELE-144

[Copilot]

Pull Request Overview

This PR fixes an issue where synapses were not being properly removed when their related neurons were deleted. The fix ensures that when a neuron is deleted, all associated synapses are also deactivated and cleaned up from the workspace state.

Key changes:

• Added a new method to deactivate synapses when a neuron is deleted
• Updated the neuron deletion handler to clean up related synapses
• Enhanced synapse visibility checking with null safety

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
workspace.ts	Added deactivateSynapsesOfNeuron method and helper function collectLeafProps to clean up synapses when neurons are deleted
SynapsesTreeViewHelpers.ts	Added null check for synapse visibility to prevent errors
SynapsesTreeView.tsx	Updated useCallback dependencies to include synapse-related state for proper re-rendering
Neurons.tsx	Modified delete handler to call synapse cleanup before neuron deletion

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[ddelpiano]

lgtm