fix(shard): handle RECONNECT opcode during initial connection flow

[shiftinv]

Summary

The first op we receive when connecting should never be anything other than HELLO, but apparently Discord thinks otherwise.
Instead of crashing completely, we now just attempt to perform the requested reconnect.

ref: https://canary.discord.com/channels/808030843078836254/1198023852601659412

Checklist

• If code changes were made, then they have been tested
  • I have updated the documentation to reflect the changes
  • I have formatted the code properly by running pdm lint
  • I have type-checked the code by running pdm pyright
• This PR fixes an issue
• This PR adds something new (e.g. new method or parameters)
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)