[Bug] Prevent unit removal on zero values within calc() function

[ghost]

🐞 Bug Report

Describe the bug

• The removal of the unit for zero values will cause the calc() function to break

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Is this a regression?

This I can't tell because I just installed this plugin for the first time

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To Reproduce

1. Enter some css sample like .element { width: calc( 100px + var(--test, 0px)) }
2. Let the extension minify the code
3. Test the minified style in the browser

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Expected behaviour

• The width should stay 100px since there's no var set and the fallback is equal to zero

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Media prove

You can live test this here https://developer.mozilla.org/en-US/docs/Web/CSS/calc()

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Your environment

• OS: Debian 11 x64
• Browser name and version: Firefox 95.0.2 64bit

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