Fix: use MarkdownConsole in non-interactive contexts

[treysp]

Some terminals do not support unicode emoji like those used in the standard CLI output (e.g., running SQLMesh with Powershell.exe in Github Actions). Using the MarkdownConsole instead of standard TerminalConsole addresses this problem.

There is not a universal way to determine whether a given terminal supports Unicode, so we instead assume that unicode is not needed in any non-interactive context (typically a CI platform).

This PR:

• Automatically detects if we're in a non-interactive context and uses MarkdownConsole if so
  • Non-interactive contexts include CI (detected via env vars commonly set by CI systems) or anywhere stdout and stdin are not both tty
• Brings the MarkdownConsole output into alignment with recent CLI updates
• Allows the user to force terminal output of any runtime environment with the SQLMESH_RUNTIME_ENVIRONMENT env var
  • Accepted values: terminal, databricks, google_colab, jupyter, debugger, non_interactive, ci