Fix message notification not appearing

[BackSH00TER]

Pull Request Description

Problem: If a user receives a text message, but has never opened the message conversation before, they will not receive a notification on their phone. Fixes issue: https://github.com/project-error/npwd/issues/1017

Repro steps:

• PlayerA just logs in and never opens their phone
• PlayerB sends a text msg to PlayerA
• Actual: PlayerA does not receive a notification
• Expected: PlayerA should receive a notification

The reason this is happening is because of the following error. We are trying to read id from activeMessageConversation which is undefined.

Fix: Instead of trying to read from activeMessageConversation we can use the convId that is already passed to the addNotification function. This is sufficient as it will always pass the id of the conversation that the msg was for and doesn't have a need to rely on the active conversation.

Additionally in the handleUpdateMessages function, there is a comparison to the activeConversation.id, which also throws a can't read id from undefined error because activeConversation could be undefined. Fixed this error by using optional chaining (?.) to make sure the variable is defined before trying to access variables from it.

Demo: https://github.com/project-error/npwd/assets/18689469/bf6751ff-c222-4304-a21d-7fb685e6aba8

• Shows a fresh restart of the phone
• PlayerA never opens their phone
• PlayerB send a msg to PlayerA
• PlayerA receives the notification

Pull Request Checklist:

• [x] Have you followed the guidelines in our Contributing document and Code of Conduct?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] Have you built and tested NPWD in-game after the relevant change?