Default responses in registration ethnicity and sex fields

[maramather]

For the ethnicity and sex questions, the default should not be one of the accepted answers, to avoid allowing subjects not to answer the question.

[noah10]

This should now be fixed.

[nashiro]

I'm not completely sure what was requested/fixed. I didn't see this github issue before I registered (so didn't pay careful attention - sorry). But I think it was originally blank (?) and I had to select African American or European American. The same for sex.

[cho890]

It was blank for me. It might be helpful for the field to reflect "select one" or something similar grayed out, and then the participant seems the options populate below after clicking on the field.

[noah10]

We can't gray out "select one" but we can put that text there. Do we want to do that or leave it the way it is? (Keeping in mind that if we do make that change we have to test it again.)