[R] How to convert the timestamp without time zone type to the POSIXct type ideally?

### Describe the bug, including details regarding any error messages, version, and platform.

The POSIXct type in R seems to behave in the absence of time zone information in such a way that it is interpreted as the time zone time in which the R session is running.

However, the arrow package does not consider the time zone of the R session when converting from the Arrow timestamp type to the POSIXct type.

``` r
library(arrow)
#>
#> Attaching package: 'arrow'
#> The following object is masked from 'package:utils':
#>
#> timestamp

Sys.setenv(TZ = "UTC")

x <- "1900-01-01"
a_a <- chunked_array(as.POSIXct(x), type = timestamp())
a_a
#> ChunkedArray
#>
#> [
#> [
#> 1900-01-01 00:00:00
#> ]
#> ]

out <- as.vector(a_a)

as.POSIXct(x)
#> [1] "1900-01-01 UTC"
unclass(as.POSIXct(x))
#> [1] -2208988800
#> attr(,"tzone")
#> [1] ""
out
#> [1] "1900-01-01 UTC"
unclass(out)
#> [1] -2208988800

Sys.setenv(TZ = "Europe/Paris")

out <- as.vector(a_a)

as.POSIXct(x)
#> [1] "1900-01-01 PMT"
unclass(as.POSIXct(x))
#> [1] -2208989361
#> attr(,"tzone")
#> [1] ""
out
#> [1] "1900-01-01 00:09:21 PMT"
unclass(out)
#> [1] -2208988800
```

^{Created on 2024-03-01 with [reprex v2.0.2](https://reprex.tidyverse.org)}

Is there a reason why this behavior was chosen? Or is this a bug and should be fixed? (which is, of course, a breaking change).

I found this behavior in this issue (pola-rs/r-polars#875)

### Component(s)

R