fix: little fixes and tests for replicated canister log fetching

[mraszyk]

This PR implements the following fix: separates the maximum size when computing a fetch_canister_logs response (checked w.r.t. estimated Rust in-memory data size) from the maximum Candid-encode size of the response (relevant for computing the cycles amount that must be attached to the call) - the latter is larger by the Candid-encoding overhead (approximated by 4KiB).

This PR also adds new tests:

• unit tests of the fee formula;
• checking that a call is rejected if too few cycles are attached (attaching just one cycle less than required to be as tight as possible);
• checking that unused cycles are refunded exactly;
• checking that the result is trimmed to be within the maximum result size and its Candid-encoded size does not exceed the corresponding constant accounting for up to 4KiB overhead.

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 7c95918.

Security Overview

• 🔎 Scanned files: 6 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/f5e9d2bb-29a4-4b64-902a-391d65fd8b2d?scanId=ed16a635-b967-465c-ab1e-b11a1ca529d4&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► rs/cycles_account_manager/src/cycles_account_manager/tests.rs       Add tests for fetch_canister_logs_fee and fee scaling behavior
Enhancement	► rs/execution_environment/BUILD.bazel       Add rs/limits to test suite dependencies
Enhancement	► rs/execution_environment/tests/canister_logging.rs       Add cycles_account_manager helpers and subnet config setup; rename/adjust tests to reflect new fee logic; integrate max fee calculations in tests
Enhancement	► rs/replicated_state/src/canister_state/system_state/log_memory_store/ring_buffer.rs       Use MAX_FETCH_CANISTER_LOGS_RESULT_BYTES to define RESULT_MAX_SIZE and document reasoning
Enhancement	► rs/replicated_state/src/canister_state/system_state/log_memory_store/tests/log_memory_store.rs       Update imports to include FetchCanisterLogsResponse, Payload and related types; use NEW constants for limits and response handling; extend tests to validate limit-related behavior and response sizing
Enhancement	► rs/types/types/src/canister_log.rs       Add MAX_FETCH_CANISTER_LOGS_RESULT_BYTES and MAX_FETCH_CANISTER_LOGS_RESPONSE_BYTES; document relationship to result size and framing; include validation consts