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]

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 ⚠️

Additional details and impacted files

@@            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              

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[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