Remove TimerMixin on ProgressBarAndroidExample.android.js (#21501)
Remove TimerMixin on ProgressBarAndroidExample.android.js (#21501)

Summary:
Related to #21485.
Removed TimerMixin from the `RNTester/js/ProgressBarAndroidExample.android.js` since it is currently not used.

- [x] npm run prettier
- [x] npm run flow-check-ios
- [x] npm run flow-check-android

In progress 🙇

[GENERAL] [ENHANCEMENT] [RNTester/js/ProgressBarAndroidExample.android.js] - remove TimerMixin dependency
Pull Request resolved: https://github.com/facebook/react-native/pull/21501

Reviewed By: TheSavior

Differential Revision: D10218375

Pulled By: RSNara

fbshipit-source-id: c4c12f65855452bc2485f034a0560afd204512f4

hammerandchisel/react-native,facebook/react-native,facebook/react-native,pandiaraj44/react-native,exponent/react-native,pandiaraj44/react-native,exponentjs/react-native,hammerandchisel/react-native,janicduplessis/react-native,javache/react-native,pandiaraj44/react-native,pandiaraj44/react-native,hoangpham95/react-native,myntra/react-native,hammerandchisel/react-native,facebook/react-native,exponentjs/react-native,exponentjs/react-native,arthuralee/react-native,janicduplessis/react-native,javache/react-native,myntra/react-native,exponentjs/react-native,arthuralee/react-native,myntra/react-native,myntra/react-native,exponentjs/react-native,hammerandchisel/react-native,facebook/react-native,exponent/react-native,exponentjs/react-native,arthuralee/react-native,janicduplessis/react-native,hoangpham95/react-native,exponent/react-native,javache/react-native,exponentjs/react-native,exponent/react-native,hoangpham95/react-native,exponent/react-native,facebook/react-native,javache/react-native,javache/react-native,janicduplessis/react-native,hoangpham95/react-native,janicduplessis/react-native,hoangpham95/react-native,myntra/react-native,facebook/react-native,facebook/react-native,myntra/react-native,facebook/react-native,facebook/react-native,exponent/react-native,hammerandchisel/react-native,janicduplessis/react-native,exponent/react-native,hammerandchisel/react-native,exponentjs/react-native,javache/react-native,hoangpham95/react-native,pandiaraj44/react-native,hammerandchisel/react-native,hoangpham95/react-native,myntra/react-native,pandiaraj44/react-native,myntra/react-native,pandiaraj44/react-native,hammerandchisel/react-native,arthuralee/react-native,hoangpham95/react-native,javache/react-native,javache/react-native,arthuralee/react-native,pandiaraj44/react-native,janicduplessis/react-native,myntra/react-native,janicduplessis/react-native,javache/react-native,exponent/react-native