copilot: Use latest Copilot API spec

[imumesh18]

Recently we started to use the new copilot-lsp which has different spec compare to the copilot.vim and it returns a lot of warnings for using the older spec. This PR upgrades it to use the latest spec.

Logs

2025-05-07T21:07:24-03:00 INFO  [lsp] Language server with id 0 sent unhandled notification window/logMessage:
{
  "type": 2,
  "message": "[sdk] setEditorInfo is deprecated. Use initializationOptions for editorInfo and editorPluginInfo and workspace/didChangeConfiguration for editorConfiguration."
}

New Docs: https://github.com/github/copilot-language-server-release/blob/main/README.md

Tasks:

• Move signIn to use latest spec.
• Move completion to use latest spec.
• Use window/showMessageRequest to show server sent notification to user. This is already handled from lsp_store.rs.
• Use window/logMessage to log messages specifically errors and other send from lsp server. This is already handled from lsp_store.rs.
• Use didChangeStatus to update copilot status update.
• Do through code cleanup
• Improve the copilot experience and remove rough edges.

I have tested it it's working now with no rough edges. Also we don't address the bigger issue of how to handle the NES(Next edit suggestions) But this sets up for the NES changes in future.

Release Notes:

• N/A

[imumesh18]

removed this as the current copilot-lsp supports windows/logMessage.