fix(Modal): support IE11, fix scrolling glitches

[layershifter]

IE11 support

Fixes #3388.
Previously we missed support for legacy mode for Modals in SUI 2.4.0, this PR adds that support.

Scrolling glitches

Fixes #2221.
This PR ports fit() function from SUI which has more accurate computations than our existing check:

const scrolling = height > window.innerHeight

centered={false}

Fixes #2891.
Fixes #3669.
This case is also covered with ported fit() function.

[codecov-io]

Codecov Report

Merging #3679 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3679      +/-   ##
==========================================
+ Coverage   99.83%   99.83%   +<.01%     
==========================================
  Files         174      175       +1     
  Lines        3103     3116      +13     
==========================================
+ Hits         3098     3111      +13     
  Misses          5        5

Impacted Files	Coverage Δ
src/modules/Modal/Modal.js	100% <100%> (ø)	⬆️
src/modules/Modal/utils/index.js	100% <100%> (ø)

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