Fix: Prevent race condition in showing toast message

[chakflying]

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Description

Showing an up/down toast message depends on getting the monitor name from monitorList. Here is the race condition:

1. Initial page load
2. server sends a very long monitorList
3. server sends a up/down heartbeat
4. client tries to show toast, but monitorList has not finished loading.

Uncaught (in promise) TypeError: this.monitorList[data.monitorID] is undefined
    initSocketIO socket.js:189
    emit index.mjs:136
    emitEvent socket.js:498

Prevent toasts from showing if monitor name cannot be obtained is a clean solution, but I'm not sure if it's optimal.

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
• My code needed automated testing. I have added them (this is optional task)

Screenshots (if any)