Rename assert_in_contract to debug_assert_in_contract

[mootz12]

What

Rename's assert_in_contract to debug_assert_in_contract, and adds a #[doc(hidden)] tag.

assert_in_contract was not deprecated as it's primarily a macro used internally.

Why

This function is primarily for internal use to provide better errors to users invoking certain env methods during tests outside of the context of a contract.

Closes #1805

Known limitations

This is public interface change, and needs to wait for the next major version macro was deprecated instead, just need a minor release

[Copilot]

Pull request overview

This PR updates Soroban SDK’s internal “in-contract” assertion macro to better communicate its intended debugging/test-only role, and applies the rename to call sites that rely on it to produce clearer errors when env methods are invoked outside a contract context during tests.

Changes:

• Rename assert_in_contract! to debug_assert_in_contract! and mark it #[doc(hidden)].
• Update Storage accessors to use the renamed macro.
• Update Prng methods/traits to use the renamed macro.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
soroban-sdk/src/lib.rs	Renames and hides the exported macro that checks “in contract” execution context in test/testutils builds.
soroban-sdk/src/storage.rs	Switches persistent(), temporary(), and instance() to call debug_assert_in_contract!.
soroban-sdk/src/prng.rs	Switches PRNG reseed/shuffle/gen/fill paths to call debug_assert_in_contract!.