Simple fix for tuncation and padding of value text

[cchaos]

This reverts the need to add a new class to component simply when the label is present. You can easily adjust the styles of an element based on the presence of an element that comes before it with the sibling selector.

.euiProgress__label + .euiProgress__valueText {
  // These styles will only be added to the valueText element
  // if the label is present because it is dependent on being the 
  // next direct sibling of the label
}

This also adjusts how the flex is handled to prioritize the valueText. I know this seems backward because the more important piece of data is the label. However, for the use case of this particular instnace, I'm expecting engineers to have control over the size of the value by rounding and such, but they most likely won't have control over the label. So if they see there is like 18 decimals attached to the percentage forcing it to grow so wide the label falls off, they should be able to do Math.round(value) before passing it in.

Before

After