fix(core): remove str() cast in get_from_dict_or_env to preserve original types

[nightcityblade]

Description

Fixes #35285.

get_from_dict_or_env accepts dict[str, Any] but was casting all dictionary values to str via str(), which breaks code storing non-string types (e.g., enums) as dict values.

Changes

• Removed str() wrapping when returning values from the dictionary
• Updated return type annotation from str to Any to match the input type
• Environment variable lookups still return strings as expected (via get_from_env)

Testing

The change is backwards-compatible: string values remain strings, but non-string types (enums, ints, etc.) are no longer incorrectly cast.

[nightcityblade]

Gentle ping — this has been approved by Christophe Bornet (@cbornet) for 3 days. The only CI failure is CodSpeed Benchmarks which appears to be a flaky infrastructure issue (all actual tests pass). Would appreciate a merge when convenient. Thanks!