Update azure functions core tool to use 4

[BartInTheField]

What did you implement:

Update the azure functions tools to use the newest version, needed for local development

How did you implement it:

Changed dependency in package.json

How can we verify it:

Todos:

Note: Run npm run test:ci to run all validation checks on proposed changes

• Ensure there are no lint errors.
  Validate via npm run lint
  Note: Some reported issues can be automatically fixed by running npm run lint:fix
• Write tests and confirm existing functionality is not broken.
  Validate via npm test
• Write documentation
• Provide verification config / commands / resources
• Enable "Allow edits from maintainers" for this PR
• [ x Update the messages below

Is this ready for review?: YES
Is it a breaking change?: NO