Adjust StatisticsCard component

What does this MR do and why?

The MR make few adjustments to StatisticsCard component added in !80261 (merged), the adjustments are needed to continue the work in !79525 (merged).

The adjustments are:

• Allow rendering the progress bar when the percentage value is 0
• Adjust margin classes in the component, so consumers can be in more control of the spacing
• Update snapshot and storybook file accordingly

Screenshots or screen recordings

N/A

How to set up and validate locally

To view the storybook:

• Run yarn storybook:start
• Visit http://localhost:9002/?path=/story/usage-quotas-components-statistics-card--default

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #350646 (closed)