Provide an error message when any instrument names are passed to
read_redcap()
that do not exist in the project metadata.
check_forms_exist(db_metadata, forms, call = caller_env())
An error message listing the requested instruments that don't exist
The metadata file read by
REDCapR::redcap_metadata_read()
The character vector of instrument names passed to
read_redcap()
the calling environment to use in the error message