Fix for #356

[DomiiBunn]

Tick the checkbox if you understand [x]:

• I have read and understand the pull request rules.

Description

Fixes #356

Added a more graceful disconnect when removing an agent to ensure socket.io is not in a "stuck" state where it attempts to keep an open connection to a deleted agent as well as a re-trigger of sendAgentList to ensure the UI has a quick update on agent deletion.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I ran ESLint and other linters for modified files
• I have performed a self-review of my own code and tested it
• I have commented my code, particularly in hard-to-understand areas
  (including JSDoc for methods)
• My changes generate no new warnings

[DomiiBunn]

I messed up with the branches. Will re-open with the correct single fix commit