feat: add support for 32-bit registry access in key_access enum

[Brainy0207]

This PR extends the key_access enum in registry_helpers.h to support 32-bit registry access. The following new values have been added:

• read32: Opens a key for reading from the 64-bit registry.
• readwrite32: Opens a key for reading and writing from the 64-bit registry.

Additionally, the get_access_flags function has been updated to handle these new enum values appropriately.

This is a follow up to #555 which added access to the 64-bit registry for 32-bit processes.
This adds access to the 32-bit registry for 64-bit processes.

Fixes #435

[Brainy0207]

It seems #632 will add write and write64 keys to key_access, so we would end up without a write32 key, if both PRs are merged. Depending on which PR gets merged first, the other one should add the write32 key then.