[Stepper]: Step separator not fully changing its styles when a step is completed

[adrianptrv]

Description

When completing a step in the Stepper, the part of the separator that falls behind the current step does not update to the completed style and color. The completed styling is only applied after moving to the next step. This occurs across all themes.

Steps to reproduce

1. Open the Stepper sample.
2. Fill in the first two fields so the step becomes completed, but do not navigate to the next step.

Result

The part of the separator that is behind the currently completed step does not receive the completed style and color.

Expected result

The separator portion behind the completed step should apply the completed style and color, like the rest of the separator.

Stepper.mp4