drop_copy / drop_move moving entire file path, not just the selected file

I'm trying to move files en masse with a for loop, but instead of just moving the selected file, it copies the entire file path when using the drop_copy or drop_move functions rather than just the single selected file.

```r
library(rdrop2)

drop_copy(from_path = 'first_folder/second_folder/File1.csv ', to_path = 'home_folder/', dtoken = ...)

```

## Expected Behaviour

What did you expect to happen from the above code?

ONLY the .csv file would appear within home_folder after copying from the path.

## Actual Behaviour

What happened instead?

There is a new folder within home_folder called second_folder that has the .csv file inside of it, rather than just copying the selected file.

## Account Type

Are you using Dropbox Basic, Dropbox Pro, or Dropbox for Business?

Dropbox Plus?

## Session Info

Replace the output below (inside the backticks) with output from `devtools::session_info()` (or `sessionInfo()` if you don't have `devtools` installed)

```r

> devtools::session_info()

─ Session info ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

 setting  value

 version  R version 4.1.1 (2021-08-10)

 os       macOS Catalina 10.15.7

 system   x86_64, darwin17.0

 ui       RStudio

 language (EN)

 collate  en_US.UTF-8

 ctype    en_US.UTF-8

 tz       America/Chicago

 date     2022-09-14

 rstudio  2022.07.1+554 Spotted Wakerobin (desktop)

 pandoc   NA


─ Packages ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

 package     * version date (UTC) lib source

 assertthat    0.2.1   2019-03-21 [1] CRAN (R 4.1.0)

 cachem        1.0.6   2021-08-19 [1] CRAN (R 4.1.0)

 callr         3.7.2   2022-08-22 [1] CRAN (R 4.1.1)

 cli           3.4.0   2022-09-08 [1] CRAN (R 4.1.2)

 crayon        1.5.1   2022-03-26 [1] CRAN (R 4.1.2)

 DBI           1.1.3   2022-06-18 [1] CRAN (R 4.1.2)

 devtools      2.4.4   2022-07-20 [1] CRAN (R 4.1.2)

 digest        0.6.29  2021-12-01 [1] CRAN (R 4.1.0)

 dplyr       * 1.0.10  2022-09-01 [1] CRAN (R 4.1.1)

 ellipsis      0.3.2   2021-04-29 [1] CRAN (R 4.1.0)

 fansi         1.0.3   2022-03-24 [1] CRAN (R 4.1.2)

 fastmap       1.1.0   2021-01-25 [1] CRAN (R 4.1.0)

 fs            1.5.2   2021-12-08 [1] CRAN (R 4.1.0)

 generics      0.1.3   2022-07-05 [1] CRAN (R 4.1.2)

 glue          1.6.2   2022-02-24 [1] CRAN (R 4.1.2)

 htmltools     0.5.3   2022-07-18 [1] CRAN (R 4.1.2)

 htmlwidgets   1.5.4   2021-09-08 [1] CRAN (R 4.1.0)

 httpuv        1.6.6   2022-09-08 [1] CRAN (R 4.1.2)

 httr          1.4.4   2022-08-17 [1] CRAN (R 4.1.2)

 later         1.3.0   2021-08-18 [1] CRAN (R 4.1.0)

 lifecycle     1.0.2   2022-09-09 [1] CRAN (R 4.1.2)

 magrittr      2.0.3   2022-03-30 [1] CRAN (R 4.1.2)

 memoise       2.0.1   2021-11-26 [1] CRAN (R 4.1.0)

 mime          0.12    2021-09-28 [1] CRAN (R 4.1.0)

 miniUI        0.1.1.1 2018-05-18 [1] CRAN (R 4.1.0)

 pillar        1.8.1   2022-08-19 [1] CRAN (R 4.1.2)

 pkgbuild      1.3.1   2021-12-20 [1] CRAN (R 4.1.0)

 pkgconfig     2.0.3   2019-09-22 [1] CRAN (R 4.1.0)

 pkgload       1.3.0   2022-06-27 [1] CRAN (R 4.1.2)

 prettyunits   1.1.1   2020-01-24 [1] CRAN (R 4.1.0)

 processx      3.7.0   2022-07-07 [1] CRAN (R 4.1.2)

 profvis       0.3.7   2020-11-02 [1] CRAN (R 4.1.0)

 promises      1.2.0.1 2021-02-11 [1] CRAN (R 4.1.0)

 ps            1.7.1   2022-06-18 [1] CRAN (R 4.1.2)

 purrr         0.3.4   2020-04-17 [1] CRAN (R 4.1.0)

 R6            2.5.1   2021-08-19 [1] CRAN (R 4.1.0)

 Rcpp          1.0.9   2022-07-08 [1] CRAN (R 4.1.2)

 rdrop2      * 0.8.2.1 2020-08-05 [1] CRAN (R 4.1.0)

 remotes       2.4.2   2021-11-30 [1] CRAN (R 4.1.0)

 rlang         1.0.5   2022-08-31 [1] CRAN (R 4.1.2)

 rstudioapi    0.14    2022-08-22 [1] CRAN (R 4.1.2)

 sessioninfo   1.2.2   2021-12-06 [1] CRAN (R 4.1.0)

 shiny         1.7.2   2022-07-19 [1] CRAN (R 4.1.2)

 stringi       1.7.8   2022-07-11 [1] CRAN (R 4.1.2)

 stringr       1.4.1   2022-08-20 [1] CRAN (R 4.1.2)

 tibble        3.1.8   2022-07-22 [1] CRAN (R 4.1.2)

 tidyselect    1.1.2   2022-02-21 [1] CRAN (R 4.1.2)

 urlchecker    1.0.1   2021-11-30 [1] CRAN (R 4.1.0)

 usethis       2.1.6   2022-05-25 [1] CRAN (R 4.1.2)

 utf8          1.2.2   2021-07-24 [1] CRAN (R 4.1.0)

 vctrs         0.4.1   2022-04-13 [1] CRAN (R 4.1.2)

 xtable        1.8-4   2019-04-21 [1] CRAN (R 4.1.0)

Start with the drop_copy and drop_move entry points and reproduce the issue using the provided R call with a nested source path. Trace how the source path is translated for the Dropbox request, then verify that copying or moving File1.csv creates only that file directly under home_folder.

Written by the indexing model from the issue text.