migration script: fix `import Blockly from 'blockly'`

[maribethb]

Check for duplicates

• I have searched for similar issues before opening a new one.

Component

migration

Problem

No response

Request

Using import Blockly from 'blockly' has never been recommended or explicitly supported. It won't work when we publish esmodules because we don't have a default export. The migration script should find and change these to import * as Blockly from 'blockly' if possible.

Alternatives considered

No response

Additional context

No response