Fix: Getting TLS certificate through proxy & prometheus update

[chakflying]

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Description

Fixes #4693
Fixes #4698
Also handles the issue in #3551 correctly

I think I found a way to listen for the secureConnect event, which eliminates the messy 2-step process of the previous fix. I also restored the old method of checking for the tlsSocket after the response is received, since the proxy-agent does not seem to work with the keylog event, but we can still obtain the TLS information through the socket.

Feel free to test.

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 generates no new warnings
• My code needed automated testing. I have added them (this is optional task)

Screenshots (if any)