fix: remove react native require cycle warning

[jadertao]

fix #236
set the alert,prompt,operation value of component Modal in components/modal/index.tsx instead of components/modal/Modal.tsx to avoid require cycle.

[codecov]

Codecov Report

Merging #242 into master will not change coverage.
The diff coverage is 85.71%.

@@           Coverage Diff           @@
##           master     #242   +/-   ##
=======================================
  Coverage   59.29%   59.29%           
=======================================
  Files         197      197           
  Lines        4936     4936           
  Branches     1082     1082           
=======================================
  Hits         2927     2927           
  Misses       1992     1992           
  Partials       17       17

Flag	Coverage Δ
#rn	59.29% <85.71%> (ø)	⬆️

Impacted Files	Coverage Δ
components/modal/Modal.tsx	79.77% <0%> (-1.28%)	⬇️
components/modal/index.tsx	100% <100%> (ø)	⬆️

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