Remove workaround for default lock code in Matter

[oyvindwe]

Proposed change

Removes the workaround for retrieving the default code in Matter locks, as it is no longer necessary after PR #103463

Note: I don't have any Matter locks, but I added a case for default code to the Matter lock unit test.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
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• Tests have been added to verify that the new code works.

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[home-assistant]

Hey there @home-assistant/matter, mind taking a look at this pull request as it has been labeled with an integration (matter) you are listed as a code owner for? Thanks!

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[Bre77]

Looks good as best I can tell.

[marcelveldt]

Just the one comment about using new style type annotations, otherwise looks good.

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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[MartinHjelmare]

Thanks!

Comment addressed