removed gzipping large csv file on form attachments page

[sadiqkhoja]

Closes #

What has been done to verify that this works as intended?

• Manually tested by uploading file and multiple files on form attachments page
• All unit and integration tests are passing

Why is this the best possible solution? Were any other approaches considered?

NA

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

NA

Does this change require updates to user documentation? If so, please file an issue here and include the link below.

NA

Before submitting this PR, please make sure you have:

• run npm run test and npm run lint and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code or assets from external sources are properly credited in comments or that everything is internally sourced

[matthew-white]

Just in case our future selves wonder why we made this change, we're updating nginx in getodk/central#391. As part of the update, it looks like we're going to drop support for request body decompression. That requires us to make this change to Frontend.