Fix disabled color foreground on FilledButton

[WinXaito]

Pre-launch Checklist

• I have run dartfmt on all changed files
• I have updated CHANGELOG.md with my changes
• I have run "optimize/organize imports" on all changed files
• I have addressed all analyzer warnings as best I could
• I have added/updated relevant documentation
• I have run flutter pub publish --dry-run and addressed any warnings

According to the normal button : https://github.com/bdlukaa/fluent_ui/blob/master/lib/src/controls/inputs/buttons/button.dart#L62

[bdlukaa]

I believe the color shouldn't be the same as Button

For light mode:

And for dark mode:

[WinXaito]

Currently I just fixed the foreground color.
So we need to change the background color.

but I agree with you.

btw how is on Microsoft fluent ?

[bdlukaa]

I'm no longer getting based on the web fluent documentation. I take examples on the Windows native apps I find

[WinXaito]

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@bdlukaa ok for you ?