Fix SIGSEGV (issue #298) and hearthbeating in voice

[oidq]

Description

• Fix SIGSEGV panic in issue SIGSEGV panic when a voice reconnect is triggered #298, function now returns non-nil error:
  "context cancelled"

• Fix opCode 3 sending before opCode 0 in voice

  • this caused "authentication error", which resulted in SIGSEGV

• Add & improve errors and logs in (re)connecting functions

Type of change

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

Checklist:

• I ran go generate
• I have performed a self-review of my own code (remember to run go fmt ./...)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• Added benchmarks if this is a performant required component (potential bottlenecks)