[Feature]: Improve binary size measurements

[alexfertel]

What is the feature you would like to see?

The check_wasm workflow outputs binary sizes for our example contracts, like this:

It would be nice to:

• Make this workflow faster by directly measuring binary size (compressed & uncompressed) instead of using cargo stylus.
• Increase the precision of the measurement, i.e., display the full size in bytes instead of the approximation in KB.
• Research if there's an easy way to display the impact in a PR comment a la codecov?

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