Add support for EFFECT_OFF

[dmulcahey]

Fixes: #98

[codecov]

Codecov Report

Attention: Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.49%. Comparing base (c394a7c) to head (81b7f70).
Report is 8 commits behind head on dev.

Files with missing lines	Patch %	Lines
zha/application/platforms/light/__init__.py	80.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev      #99      +/-   ##
==========================================
+ Coverage   96.45%   96.49%   +0.04%     
==========================================
  Files          61       61              
  Lines        9336     9337       +1     
==========================================
+ Hits         9005     9010       +5     
+ Misses        331      327       -4     

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[dmulcahey]

@puddly @TheJulianJES do we want to do this color mode part: https://developers.home-assistant.io/blog/2024/01/23/light-color-mode-changes/#requirements-on-color_mode-are-less-strict-when-a-light-is-rendering-an-effect

[TheJulianJES]

Can't comment on unchanged lines, but the assume option for effects should be changed to be like the others.
So, adding the is not None check. Line 1383 and following currently.

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do we want to do this color mode part

We could do that, yeah. (would prefer a separate PR though)
IIRC, changing the color during a colorloop effect doesn't impact the bulb, so we could set the color modes to on_off and brightness during that. Brightness changes still affect it, I think.

(On a semi-related note, I'd also really like to support Hue effects in the future. Will require changes to both quirks and zha.)

[TheJulianJES]

I've rebased the PR to fix the conflicts and addressed the comments I just made above. There's some more context in those comments on why the changes are needed IMO.

[TheJulianJES]

I think this PR should be ready now. The missing coverage is on existing lines, something to improve in the future.

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Also discovered an existing (long-standing) issue when turning off effects via changing the color, but it's unrelated to this PR. Filed #210. Also something to be fixed in the future. The effect code on/off should be cleaned up a bit with it. Looks like nobody reported this before.