Improve error message for streaming on old host version

[ejizba]

Users need v4.28 or higher for stream support. I updated the error message they see if they're on an older version.

Before:

Worker was unable to load entry point "dist/src/index.js": coreApi.log is not a function

After:

Worker was unable to load entry point "dist/src/index.js": HTTP streaming requires Azure Functions Host v4.28 or higher.