feat(shell): add brightness_value and brightness_mode

[Xiaojun0822]

1、The current brightness value can be obtained through brightness_value 2、You can use brightness_mode to determine whether the current brightness adjustment is automatic or manual

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 53.84615% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 30.55%. Comparing base (c8e6235) to head (7a1261c).

Files	Patch %	Lines
adbutils/shell.py	42.85%	12 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #115 +/- ## ========================================== + Coverage 30.35% 30.55% +0.20% ========================================== Files 15 15 Lines 1980 2003 +23 Branches 315 322 +7 ========================================== + Hits 601 612 +11 - Misses 1360 1372 +12 Partials 19 19 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[codeskyblue]

I suggest use property to get brightness instead of function. also brightness can also accept set

Example usage

print(d.brightness)
d.brightness = 80

print(d.brightness_mode) # output BrightnessMode.AUTO | BrightnessMode.MANUAL
d.brightness_mode = BrightnessMode.AUTO

here the BrightnessMode parent class is (int, enum.Enum)

[Xiaojun0822]

I suggest use property to get brightness instead of function. also brightness can also accept set

Example usage

print(d.brightness)
d.brightness = 80

print(d.brightness_mode) # output BrightnessMode.AUTO | BrightnessMode.MANUAL
d.brightness_mode = BrightnessMode.AUTO

here the BrightnessMode parent class is (int, enum.Enum)

Modified as required