fix: region provider now respects chained profiles (#1183)

* fix: region provider now respects chained profiles
update: profile chain creation for load_credentials

* update: CHANGELOG.next.toml

* Update aws/rust-runtime/aws-config/src/profile/region.rs

Co-authored-by: John DiSanti <jdisanti@amazon.com>

Co-authored-by: John DiSanti <jdisanti@amazon.com>