Abort samsungtv discovery of legacy devices when unique id not available

[bdraco]

Proposed change

Fixes #69374

• The legacy devices have no rest api to compare the UDN
  against to ensure we have the one we use for the unique id

• We still need to proceed through the first part of the
  discovery to ensure we update any url if the device
  is already configured

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)
• 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

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[probot-home-assistant]

Hey there @chemelli74, @epenet, mind taking a look at this pull request as it has been labeled with an integration (samsungtv) you are listed as a code owner for? Thanks!
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