Fix index out of bounds panic when map collection has odd items

[dkropachev]

Summary

• Fixes index out of bounds panic in map collection to CassCqlValue conversion when a map has an odd number of items (missing value in a key-value pair)
• Changes From<&CassCollection> to TryFrom<&CassCollection> for CassCqlValue, returning CassError::CASS_ERROR_LIB_INVALID_VALUE_TYPE instead of panicking
• Updates binding.rs to use try_into() to propagate the error to callers
• Logs an error via tracing::error! when an odd-item map is encountered
• Adds Vec::with_capacity for map pair allocation
• Adds unit test covering both odd (error) and even (success) item counts

Fixes #411

Test plan

• Run cargo test collection:: to verify all collection tests pass
• Run make check-cargo-clippy check-cargo-fmt to verify linting passes

[dkropachev]

Regarding the review comment about returning an error instead of ignoring odd-item maps:

Done. Changed the implementation to return an error:

1. Changed impl From<&CassCollection> to impl TryFrom<&CassCollection> with type Error = CassError
2. Added validation that returns Err(CassError::CASS_ERROR_LIB_INVALID_VALUE_TYPE) when the map has an odd number of items
3. Updated binding.rs to use try_into().map(Some) to properly propagate the error
4. Added unit test that verifies the error is returned for odd-item maps

[wprzytula]

@dkropachev Please update the cover letter.

[dkropachev]

@dkropachev Please update the cover letter.

done

[dkropachev]

@Lorak-mmk , could you please review it ?

[dkropachev]

Just in case, cicd failure not related to this PR.