[R] Arrays containing -2147483648 are converted to NA in R

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

R uses -2147483648 (int32_min) to represent missing integer values (`NA`). When converting Arrow arrays to R using the C API and then casting to R vectors using `as.vector`, arrays containing -2147483649 and below are converted to bit64::integer64, but if the minimum value of the array is exactly -2147483648, all the -2147483648s are converted to NA. This is an edge case but it's an important one, because int32_min is often used as a special sentinel value.

Arrow should update the out-of-range check that decides whether to convert to bit64::integer64, to use -2147483647 as the minimum valid int32 rather than -2147483648.

### Component(s)

R