(re-)implement as_flights_pacakges test patch

[alex-gable]

allows for passing as_flights_package test, without altering existing behavior, by:

1. building the package in a temp directory, bypassing the error generated by usethis::create_package()
   • using a tmp directory causes the valid CRAN package name check to fail, so we also pass check_name = FALSE through this function to usethis::use_description()
2. removing the assertion of an .Rproj file existing in the package directory
   • create_package uses usethis::use_rstudio(), which we want if we're creating our own copy of the package. The function tries to place an .Rproj file in the package directory, which unfortunately forces a prompt that we can't answer in the non-interactive session, failing the test.

(follow up from #15)