fix: Hide content highlight on comment drag, update on resize.

[johnnesky]

The basics

• [x] I validated my changes

The details

Resolves

Fixes https://github.com/google/blockly-samples/issues/2330

Proposed Changes

Temporarily hides the content highlight when a workspace comment drag is initiated, and reveals it with an updated rectangle when the drag is completed. This is consistent with how block drags are handled.

When a workspace comment resize is completed, the content highlight rectangle is updated. (There's currently no event representing the start of a resize drag, but it's better than nothing.)

Reason for Changes

For consistency with moving regular blocks.

Test Coverage

None.

Documentation

N/A

Additional Information

This PR should not be submitted until the an update is published for the core Blockly library containing: https://github.com/google/blockly/pull/8217