fix #165 and update dummy sensor example

[chicco785]

Proposed changes

• Fix Issue removing a device #165
• Following the fix of the default entity generation name policy, also the example needs update.

Types of changes

What types of changes does your code introduce to the project: Put
an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing
  functionality to not work as expected)

Checklist

Put an x in the boxes that apply. You can also fill these out after
creating the PR. If you're unsure about any of them, don't hesitate to
ask. We're here to help! This is simply a reminder of what we are going
to look for before merging your code.

• I have read the CONTRIBUTING doc
• I have signed the Contributor License Agreement
• I have updated the CHANGE LOG
• I have added tests that prove my fix is effective or that my
  feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in
  downstream modules

Further comments

N/A

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️