Disable Preparation Sheet download for shotgun sequencing runs

[AmandaBirmingham]

Currently Labman offers the user the ability to download a "Preparation Sheet" (aka prep info file) for shotgun experiments (see middle entry in list below):

However, per Rodolfo, "We [the wet lab] don't generate a prep info file for metagenomics"; this is currently done by Gail, and the format/contents of the file that Labman currently creates does not match that of the file that Gail produces.

Since the wet lab does not currently create prep info files for shotgun runs, creating them in Labman is not a requirement for soft launch; the ability to create these for shotgun runs should be removed from the interface until such time as the files are generated to meet Gail's specifications.

[AmandaBirmingham]

For interface consistency, please follow the approach used in the pools list, in which the button (in that case, "Download Pool File") is simply not displayed in the cases where it is irrelevant or not supported (see entry for pool 2 below):