Prepare CTIS dashboard for survey end

[capnrefsmmat]

On June 25, 2022, CTIS will stop sampling new respondents, and sample size will decline to 0 over the following few days. We should prepare the survey dashboard for this in two ways:

1. Add a banner or text at the top of the page saying that CTIS will end on June 25 (and after June 25, switch it to say that it has ended). This can link to our end of survey page.
2. Adjust the default date mechanism to not pick dates later than June 25, and stop all the graphs at June 25 as well, so that in the following several months, the graphs continue to show the data up to June 25. That's better than the graphs gradually going blank because there's no current data.