fix: allow unwrap() in RustCrypto cipher test code

Add #[allow(clippy::unwrap_used)] attribute to the RustCrypto cipher test
module to permit unwrap() calls in test code while maintaining strict
safety in production code.

This matches the pattern established in the HAL cipher tests where:
- Production code remains panic-free (no unwrap/expect/panic)
- Test code can use unwrap() for fail-fast behavior and cleaner assertions
- Tests are meant to panic immediately when assumptions are violated

Resolves clippy warnings about unwrap usage in the comprehensive AES-CTR
test suite while preserving test readability and maintaining security
guidelines for production code.

Author: rusty1968

platform/impls/rustcrypto/src/cipher.rs

@@ -367,6 +367,7 @@ impl CipherStatus for AesCtrContext {
 }
 
 #[cfg(test)]
+#[allow(clippy::unwrap_used)]  // Allow unwrap in tests for cleaner test code
 mod tests {
     use super::*;
     use openprot_hal_blocking::cipher::BlockAligned;