arrow

GH-42240: [R] Fix crash in ParquetFileWriter$WriteTable and add WriteBatch (#42241)

### Rationale for this change

See https://github.com/apache/arrow/issues/42240.

### What changes are included in this PR?

- Fixes a crash in `ParquetFileWriter$WriteTable` by asserting the class of what's passed in and stopping if it's not a `Table`
- Since I was already there, added `WriteBatch` to match [`pyarrow.parquet.ParquetWriter.write_batch`](https://arrow.apache.org/docs/python/generated/pyarrow.parquet.ParquetWriter.html#pyarrow.parquet.ParquetWriter.write_batch) which is just a convenience
- Adds a test for the behavior of trying to write to a closed sink
- Bumps the minimum Arrow C++ test version we test the R package with on CI from 13 to 15
- Removes one ARROW_VERSION_MAJOR >= 15 guard

### Are these changes tested?

Yes.

### Are there any user-facing changes?

New method on ParquetFileWriter (WriteBatch).
* GitHub Issue: #42240

Authored-by: Bryce Mecum <petridish@gmail.com>
Signed-off-by: Jonathan Keane <jkeane@gmail.com>