luis:build parse lu file with incorrect locale priority

[feich-ms]

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Describe the bug

When users use luis:build to publish lu files, the locale of that lu file will be specified under such priority
Culture from file name(a.en-us.lu) > Culture from lu file setting(@> !# @app.culture = en-us) > default culture(default to en-us if not specified by users).

However, in current implementation, the culture passed to build function in luisCollate is default culture instead of culture from file name. This will introduce parser errors when default culture is set to other unreasonable values.

To Reproduce

Steps to reproduce the behavior:

1. use luis:build to publish a lu file with below definitions but set defaultCulture to it-it
   @ prebuilt personName
2. You will see some warings and errors like below

[WARN]: Requested PREBUILT entity "personName is not available for the requested locale: it-it
  Skipping this prebuilt entity..

The model name { personName } are reserved.

Expected behavior

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Additional context

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[bug]