Improve behavior on errors when importing a dataset #45
Description
When using the functionality of loading/importing a dataset from the Epidata API and a bad request is made, a popup appears that says "Failed to fetch API data from API Link" (and it provides the link). Dismissing that popup also dismisses the "Load from Epidata API" popup, along with all the options selected or input into it. This is not very helpful or informative.
Make the error popup provide more useful information (like an error code any any messages returned by the API) and do not clear the previously chosen parameters (so it will be easier for the user to fix their bad request).
edit:
- [strikethrough text covered by Retain form choices in "Load" dialog #62]