Remove duplicate `DeviceState.boot_time` attribute

[lunkwill42]

This was discovered in a code-review a while back. This removes the incorrect duplicate from DeviceState. The latter definition is correct, and would override the first, thanks to how Python works, so this doesn't change anything, it just cleans up.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions[bot]]

Test results

    3 files      3 suites   33s :stopwatch: 289 tests 289 :heavy_check_mark: 0 :zzz: 0 :x: 867 runs  865 :heavy_check_mark: 2 :zzz: 0 :x:

Results for commit 23e50cd7.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.82%. Comparing base (4a0ede1) to head (23e50cd).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #185 +/- ## ========================================== - Coverage 98.82% 98.82% -0.00% ========================================== Files 40 40 Lines 5422 5421 -1 ========================================== - Hits 5358 5357 -1 Misses 64 64 ```

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