`trackdown_auth()` ignores 'path' parameter

[kalenkovich]

Running trackdown_auth(path = json_path) ignores the JSON file at json_path.

To reproduce:

1. Authenticate with an app that doesn't use a given JSON.
2. Run

   json_path <- "path/to/test.json"
   trackdown::trackdown_auth(path = json_path) # This doesn't work

3. The web page that opens refers to the app from stage 1, not the app connected to the JSON file.

As far as I can tell, this is due to the fact that path hasn't been processed in any way by the time the following line is run in trackdown_auth:

app = trackdown_oauth_client() %||% trackdown_client()

It also looks like path is silently ignored by gargle::token_fetch() within trackdown_auth since the following doesn't raise an error:

trackdown::trackdown_auth(path = random_undefined_variable)

I worked around this issue by running trackdown_auth_configure(path = json_path) before running trackdown_auth. Would it make sense to do that at the top of trackdown_auth if path is specified? E.g., add

if (!is.null(path)) {
  trackdown_auth_configure(path = path)
}