[SDK-1756] Remove HTML5 novalidate attribute from Lock form

[stevehobbsdev]

Changes

This change removes the HTML5 novalidate attribute, preventing the browser
from performing its own native validation and allowing Lock to do its
validation instead.

The native validation prevented users from submitting email addresses such as
"téstiñg.üsêr@example.com", which is a valid value on the Auth0 server side.

References

Raised through internal service desk ticket.

Testing

Tested manually. Cannot test through integration testing as the client-side
native validation does not kick in.

• This change adds unit test coverage
• This change adds integration 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

[stevehobbsdev]

Build is failing but the fix is in #1889, will rebase once that PR is merged.