fix: BIP39 use given language to generate mnemonics;

[JeneaVranceanu]

Summary of Changes

One of the users raised an issue where using a language any but English produces only English BIP39 mnemonics. This PR addresses the issue and adds a test to make sure each language uses the correct words.

Original report: https://discord.com/channels/852230666292559882/855075850771496971/1223929794383839293

Test Data or Screenshots

None.

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[JeneaVranceanu]

To fix: https://github.com/web3swift-team/web3swift/actions/runs/8501186283/job/23283849799?pr=852#step:6:3856

[yaroslavyaroslav]

@JeneaVranceanu It's broken because of too new method in the tests /Users/runner/work/web3swift/web3swift/Tests/web3swiftTests/localTests/BIP39Tests.swift:20:51: error: 'split(separator:maxSplits:omittingEmptySubsequences:)' is only available in macOS 13.0 or newer let wordsOfNewMnemonic = newMnemonics.split(separator: language.separator).map { String($0) }

I believe, nothing should go wrong if to mark this given tests with a proper @availabile modifier.