fix: from_pylist covariance

[Flamefork]

Pyright reports the following correct code as an error:

a = [{"asd": 1}]
pa.Table.from_pylist(a)

error: Argument of type "list[dict[str, int]]" cannot be assigned to parameter "mapping" of type "list[Mapping[str, Any]]" in function "from_pylist"
    "list[dict[str, int]]" is not assignable to "list[Mapping[str, Any]]"
      Type parameter "_T@list" is invariant, but "dict[str, int]" is not the same as "Mapping[str, Any]"
      Consider switching from "list" to "Sequence" which is covariant (reportArgumentType)

This PR fixes this error by following the suggestion in the error report.