Fix/cancel draw

[TrevorBurgoyne]

Fix/cancel draw

Description

• Fix bug where vanish mode was disabled during brush/erase mode
• Align undo behavior for polygons and polylines with that of other annotations (once complete, the undo will delete the entire annotation rather than undoing only the last point)
• Escape keybind to cancel an in-progress annotation

PR Checklist

• Merged latest main
• Version number in package.json has been bumped since last release
• Version numbers match between package package.json and src/version.js
• Ran npm install and npm run build AFTER bumping the version number
• Updated documentation if necessary (currently just in api_spec.md)
• Added changes to changelog.md

Breaking API Changes

Undo behavior has changed for polygons and polylines such that it is consistent with other annotation types. Once complete, the undo will delete the entire annotation rather than undoing only the last point.