Fix bug on expose-production.ts

[frtGoncalo]

Fix bug when exposing the styles to the window

Description

Fixing bug caused on the 1.3.7 release that broke the dontAppendStylesToHead flag when set to true

Additional context

When running dynamicLoadingCss throws error saying cannot read name of undefined;
To test just run Module with dontAppendStylesToHead, set to true in the current version(1.3.9) the error happens

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Code of Conduct and follow the Commit Convention guidelines.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[Jiannan-dev]

Thanks