Fix schema mismatch

[HiromuHota]

As demostrated in test_append_with_schema below,

def test_append_with_schema(tmpdir):
    """Ensure we can append to a table with a schema"""
    tmpdir = str(tmpdir)
    df = pd.DataFrame({"a": [1, 2, 3, 4]})
    ddf = dd.from_pandas(df, npartitions=2)
    schema = pa.Schema.from_pandas(df)
    to_deltalake(tmpdir, ddf, schema=schema)
    to_deltalake(tmpdir, ddf, schema=schema, mode="append")

this fails as of 032253f in main branch due to "Schema of data does not match table schema" because we currently compare pyarrow.Schema (as in schema) and arro3.core.Schema (as in table.schema().to_arrow()).

dask-deltatable/dask_deltatable/write.py

Lines 144 to 153 in 032253f

	if table: # already exists
	if (
	schema is not None
	and schema != table.schema().to_arrow()
	and not (mode == "overwrite" and overwrite_schema)
	):
	raise ValueError(
	"Schema of data does not match table schema\n"
	f"Table schema:\n{schema}\nData Schema:\n{table.schema().to_arrow()}"
	)

We should align the schema class before comparison.

[HiromuHota]

Just a refactoring.
Before: DeltaSchema -> Arro3Schema -> PyArrowSchema
After: DeltaSchema -> PyArrowSchema