fix(Flex.Item): shrink issue

[kuzhelov]

This PR introduces fix for shrink prop of Flex.Item component. Previously value of 0 was improper interpreted, so that resulting flex item was remaining shrinkable even with this value provided

// no effect - still shrinkable :(
<Flex.Item shrink={0}>
  ...
</Flex.Item>

[mnajdova]

Looks good!

[codecov]

Codecov Report

Merging #1086 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master    #1086   +/-   ##
=======================================
  Coverage   81.78%   81.78%           
=======================================
  Files         702      702           
  Lines        8580     8580           
  Branches     1172     1245   +73     
=======================================
  Hits         7017     7017           
  Misses       1548     1548           
  Partials       15       15

Impacted Files	Coverage Δ
...src/themes/teams/components/Flex/flexItemStyles.ts	16.66% <0%> (ø)	⬆️

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[bmdalex]

I know this is already merged, sorry for not being able to review before that. However, there are a few things I'd like to mention.

1. what about the global values as string?

I think we should allow users to pass these too (see: https://developer.mozilla.org/en-US/docs/Web/CSS/flex-shrink#Syntax)

2. what about the true boolean value?

From the new code it looks like

<Flex.Item shrink>
  {/* some element */}
</Flex.Item />

will have no effect; to me that's not expected user behavior since the type of shrink prop is still boolean | number

[kuzhelov]

Let me start with the second question first - yes, this is exactly the effect you've described. The logic is correct as<Flex.Item shrink /> is, essentially, equivalent to <Flex.Item />, given that flex items are shrinkable by default (we've done it to correspond to CSS specs).

Speaking of the first question - we might want to introduce support for mentioned props later, but for now extra prop values from the scope of Flex component were omitted in order to achieve the following:

address as many scenarios with the least set of props/values necessary

Thus, might suggest to leave it as is for now and return to the question of introducing these prop values (or use another solution approaches) when there will be an appealing use case for that.