Summary:
This diff fixes a UI bug in export data sheet where the plugin names are stuck to the left and also the bottom buttons are stuck together with no padding. I have also added snapshot test for the same. In order to write test and reduce the complexity I changed the `ExportDataPluginSheet`'s connect method.
Bug:
{F231521086}
Reviewed By: mweststrate
Differential Revision: D20459692
fbshipit-source-id: 1047d6b38738691d682ad6e4ccec45c05e14cbbe
f889dc5e40