[EuiProgress] Allow max property to be undefined

[i-a-n]

Spent some time chatting in Slack about this, and was advised to make an issue. Here's the summary of the problem:

The max property alleges that it accepts either a number, or undefined, which checks out when I do either of these:

<EuiProgress max={100} />
<EuiProgress max={undefined} />

.. but TypeScript fails to compile when I do this:

<EuiProgress max={someCondition ? 100 : undefined} />

This doesn't seem to be a TypeScript bug or anything, since this pared-down example still works.

I was able to solve this temporarily by just doing this:

{someCondition ? (
  <EuiProgress max={100} />
) : (
   <EuiProgress />
)}

But I'd like to request that max really would accept undefined so that max={someCondition ? 100 : undefined} would work. Thanks!

[thompsongl]

Stems from the way that max is defined in the context of ExclusiveUnion.

#2984 would alleviate the problem, also, but I'm unsure how far off that work is.

[myasonik]

I don't think anyone is working on it and this seems like a much smaller thing to tackle