Add is_volume_muted property to vizio integration

[raman325]

Proposed change

Adding the is_volume_muted property to the vizio integration. Since this is being pulled directly from the device, there are no tests to add, so the existing tests have just been updated to account for the change in logic

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

The integration reached or maintains the following Integration Quality Scale:

• No score or internal
• 🥈 Silver
• 🥇 Gold
• 🏆 Platinum

[codecov]

Codecov Report

Merging #32332 into dev will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev   #32332      +/-   ##
==========================================
- Coverage   94.75%   94.75%   -0.01%     
==========================================
  Files         773      773              
  Lines       56047    56117      +70     
==========================================
+ Hits        53106    53172      +66     
- Misses       2941     2945       +4     

Impacted Files	Coverage Δ
homeassistant/components/lovelace/const.py	94.59% <0.00%> (-5.41%)	⬇️
homeassistant/helpers/storage.py	91.81% <0.00%> (-3.42%)	⬇️
homeassistant/components/gdacs/sensor.py	98.80% <0.00%> (-1.20%)	⬇️
homeassistant/components/teksavvy/sensor.py	97.75% <0.00%> (-0.03%)	⬇️
homeassistant/components/startca/sensor.py	97.93% <0.00%> (-0.03%)	⬇️
homeassistant/components/yr/sensor.py	88.05% <0.00%> (ø)	⬆️
homeassistant/components/demo/sensor.py	100.00% <0.00%> (ø)	⬆️
homeassistant/components/awair/sensor.py	95.09% <0.00%> (ø)	⬆️
homeassistant/components/deconz/sensor.py	96.82% <0.00%> (ø)	⬆️
homeassistant/components/glances/const.py	100.00% <0.00%> (ø)	⬆️
... and 18 more

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[springstan]

LGTM ✌