TYP: narrow type bounds on extract_array
xref https://github.com/pandas-dev/pandas/issues/37715

Narrowing the type bound allows resolving some ignored mypy errors.
The other modified code is needed because `extract_array` no longer returns `Any`, causing more strict type checking in the calling methods.
@twoertwein @simonjayhawkins good here? Thanks @iasoon. https://github.com/pandas-dev/pandas/pull/46942#discussion_r866212272 can be followed up with in a subsequent PR if needed  > Thanks @iasoon. [#46942 (comment)](https://github.com/pandas-dev/pandas/pull/46942#discussion_r866212272) can be followed up with in a subsequent PR if needed

not needed. Thanks @iasoon 