fix(ExcelExport): Create JSZip with .default().

[gedinakova]

Closes #8940
Because of the way JSZip is imported in our project, the way we create the object needs to be changed.

const xlsx = new JSZip(); can be used when the import statement "import JSZip from "jszip";" format is allowed. When using "import * as JSZip from "jszip";" it would throw an error in the console "JSZip is not a constructor".

This may be tested here.
In Hello.component.ts, comment line 22, uncomment line 25 and check the console to see the error.

Additional information (check all that apply):

• Bug fix
• New functionality
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• CI/CD

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• This PR includes unit tests covering all the new code (test guidelines)
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