Fix to constants and setBarStyle

[testshallpass]

• Rework PR: apply active bar style to android apply active bar style to android #207
• [react-native-web] Cannot assign to read only property [react-native-web] Cannot assign to read only property #204

[codecov-io]

Codecov Report

Merging #210 into master will decrease coverage by 0.17%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #210      +/-   ##
==========================================
- Coverage   90.39%   90.22%   -0.18%     
==========================================
  Files          11       11              
  Lines         229      225       -4     
==========================================
- Hits          207      203       -4     
  Misses         22       22

Impacted Files	Coverage Δ
constants.js	100% <100%> (ø)	⬆️
DropdownAlert.js	88.23% <100%> (-0.13%)	⬇️

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