MudThemeProvider: Fix BL0007, avoid direct parameter writes, remove MudThemingProvider, and other improvements

[ScarletKuro]

Description

IsDarkMode is using ParamterState framework.
I couldn't really do the same for Theme as I don't think BuildTheme can be made async because of this

MudBlazor/src/MudBlazor/Components/ThemeProvider/MudThemingProvider.razor

Line 15 in e1de7c8

@((MarkupString)BuildTheme())

So I ended up doing in old fashion. Let me know if I'm wrong.
watchDarkThemeMedia is now automatically subscribed on first render, it's necessary because otherwise two way binding IsDarkMode will never ever be called if you don't call WatchSystemPreference() which I don't think is a good default behavior, otherwise the IsDarkMode shouldn't be two way bindable at all.

Added JS stopWatchingDarkThemeMedia to unsubscribe from the event (before it never was), I know there is only one theme provider during the lifetime, but I think when you use automode you will end up having two subscription and this is not desired (but this is theory, I'm not an auto user), it doesn't bring any harm, just allocated additional memory if it stays.
Did an overall cleanup of the JS script:

1. The darkThemeMediaQuery was defined, yet only used for single function, when it could be reused.
2. The dotNetHelper in darkModeChange wasn't used, it's not needed.
3. The e wasn't used, which is a small mistake, because you are invoking the matchMedia once again, when you already got a result.

How Has This Been Tested?

Visually, but just docs, I don't know if i should tests some other scenarios? pls, let me know
New simple bUnit tests.

Type of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (fix or improvement to the website or code docs)

Checklist

• The PR is submitted to the correct branch (dev).
• My code follows the code style of this project.
• I've added relevant tests.

[codecov]

Codecov Report

Attention: Patch coverage is 98.03922% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 90.09%. Comparing base (28bc599) to head (b638bbb).
Report is 90 commits behind head on dev.

Files	Patch %	Lines
...Components/ThemeProvider/MudThemeProvider.razor.cs	98.00%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #8712      +/-   ##
==========================================
+ Coverage   89.82%   90.09%   +0.26%     
==========================================
  Files         412      419       +7     
  Lines       11878    12190     +312     
  Branches     2364     2400      +36     
==========================================
+ Hits        10670    10982     +312     
+ Misses        681      668      -13     
- Partials      527      540      +13     

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[danielchalmers]

Ran it on my prod app that has custom colors and System/Light/Dark modes and all seems the same

[ScarletKuro]

Removed MudThemeProvider.
Let me know if we need to have a better naming for the MudThemingProvider.

[mikes-gh]

Removed MudThemeProvider. Let me know if we need to have a better naming for the MudThemingProvider.

As discussed lets name it to the old name MudThemeProvider and document the removal of MudPopoverProvider. Might be easier in a separate PR IDK

[mikes-gh]

@ScarletKuro thanks . Probably need to add <MudPopoverProvider/> in a few places

[ScarletKuro]

I think that's all places, let me know if I missed something,

[mikes-gh]

@ScarletKuro Thanks 👍

[mikes-gh]

Maybe we should change the title for release notes?

MudThemeProvider: Fix BL0007, not write to parameter directly, remove MudThemingProvider and other improvements (#8712)?

[ScarletKuro]

Added to v7.0.0 Migration Guide #8447

[henon]

Added Warning box to make it clear and not easily overlooked.