The API token policy dialog now supports light and dark modes. This

involved updating the CodeMirror instance to make use of the same theme

that the standard rich text editors use, updating the defaults for

the .CodeMirror style, and moving the syntax highlighting theme into

the common bundle.
The token policy dialog now uses Ink buttons instead of standard

input-based buttons.

Tested the editor, styles, and selections in light and dark mode.
Tested all buttons and their expected behavior.