Files: servo/components/layout_2020/positioned.rs

PR Description:
Issue:
Improved the code in servo/components/layout_2020/positioned.rs by using mem::take instead of mem::replace for setting default values. This makes the code cleaner and more idiomatic.

Changes:
let old_min_size = mem::take(&mut self.computed_min_size);
-This change uses mem::take, which automatically provides the default value of Au, eliminating the need to specify Au::zero() explicitly.

Impact:
The change improves code readability and makes it more idiomatic by using mem::take.

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• These changes fix Prefer mem::take over mem::replace with default value #33945

• There are tests for these changes OR
• These changes do not require tests because does not alter functionality.