Fix issue when T&C URL is null

[jzonthemtn]

Describe the bug When a value for the TC_URL is not set, there will be an error.

To Reproduce Don't set a value for the TC_URL environment variable. Look in the code for an error about size.

Expected behavior The code should not display a Terms and Conditions link if TC_URL is not set.

[jzonthemtn]

<% if Rails.application.config.terms_and_conditions_url.size > 0 %>

Should probably change .size to something that is null-safe.

[jzonthemtn]

This issue may affect other environment variables so might a good idea to check the use of others, too.

[epugh]

I took a pass on the other urls to make sure okay, and they were!