Sandpack February Update

Features:

• Add logLevel to sandpack options #378.

Bugs:

• Improve the reliability of the "user-visible" mode #343;
• OpenInCodeSandboxButton: preserve ?file= param for big sandboxes #357;
• SandpackCodeViewer: make CM view read-only #390;
• Sort decorators before pass to CodeMirror #385;
• Performance improvement: don't make unnecessary sync updates #377;
• Filter out events originating from different iframes (potential memory leak) #370.