[Slider] Fix green Slider example color

[romoore]

The "Green slider without hollow circle at 0" was not green.

Before

After

[codecov-io]

Codecov Report

Merging #3292 into develop will increase coverage by 0.07%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #3292      +/-   ##
===========================================
+ Coverage    52.58%   52.65%   +0.07%     
===========================================
  Files          180      183       +3     
  Lines        25006    25215     +209     
  Branches      1204     1211       +7     
===========================================
+ Hits         13149    13278     +129     
- Misses       11783    11862      +79     
- Partials        74       75       +1

Impacted Files	Coverage Δ
...nBar/src/ColorThemer/MDCNavigationBarColorThemer.m	100% <0%> (ø)	⬆️
...ents/schemes/Color/src/MDCLegacyTonalColorScheme.m	0% <0%> (ø)
...mponents/schemes/Color/src/MDCLegacyTonalPalette.m	72.34% <0%> (ø)
...omponents/schemes/Color/src/MDCLegacyColorScheme.m	55.93% <0%> (ø)
components/NavigationBar/src/MDCNavigationBar.m	83.33% <0%> (+0.84%)	⬆️
components/Dialogs/src/MDCAlertController.m	39.05% <0%> (+12.28%)	⬆️

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