[r] Disallow writing character and raw arrays

[mojaveazure]

The R API allows sparse and dense arrays to have a type of arrow::utf8(), which is disallowed by the spec (primitives only). If the user attempts to create an array of characters, the R API should error out

Dense array example:

> uri <- tempfile("r-dense-character")
> strings <- matrix("", nrow = 200L, ncol = 100L)
> (atype <- arrow::infer_type(strings))
[1] Utf8
     string
> arr <- SOMADenseNDArrayCreate(uri, type = atype, shape = dim(strings)) # This should error
> arr$write(strings)
> arr$close()
> arr <- SOMADenseNDArrayOpen(uri)
> arr$read_arrow_table()$soma_data$type
[1] LargeUtf8
     large_string

Sparse array example

> uri <- tempfile("r-sparse-character")
> shape <- c(200L, 100L)
> ij <- sample.int(prod(shape), size = floor(0.6 * prod(shape))) - 1L
> coo <- data.frame(soma_dim_0 = ij%%shape[1L], soma_dim_1 = ij%/%shape[1L], soma_data = "")
> (atype <- arrow::infer_type(coo$soma_data))
[1] Utf8
     string
> arr <- SOMASparseNDArrayCreate(uri, type = atype, shape = shape) # This should error
> arr$.write_coordinates(coo)
> arr$close()
> arr <- SOMASparseNDArrayOpen(uri)
> arr$read()$tables()$concat()$soma_data$type
[1] LargeUtf8
     large_string

Likewise, raw should be disallowed (Arrow maps to Uint8, but this should be Binary, which is also disallowed by the spec)