Header height not updated when Lock dialog is closed and reopened

[adamjmcgrath]

Changes

Make sure headerHeight is set whenever the component mounts. So that when the Lock dialog is close and reopened, its header height gets calculated again.

Also, had to handle a couple of lint errors to pass the pre-commit hook

References

Fixes #1870

Testing

Close and reopen the Lock modal, confirm that the header does not obscure the form on the second opening.

Also tested in IE11

• This change adds unit test coverage
• This change has been tested on the latest version of the platform/language

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors
• All code quality tools/guidelines have been run/followed
• All relevant assets have been compiled
• All active GitHub checks have passed