investigate whether CSS clip-path adds a fingerprinting risk

Support for applying CSS clip-path to DOM elements was added during the ESR60 development cycle. We should verify that this feature does not add any fingerprinting risks, e.g., due to platform, OS, or GPU-specific behavior. See: ​https://developer.mozilla.org/en-US/docs/Web/CSS/clip-path ​ https://bugzilla.mozilla.org/show_bug.cgi?id=1247229