UUT - Colours for limits and measurements in the diagram

Use consistent colours for measurements and limits in graphs in UUT. If I have a graph with an upper and lower limit, the limits are displayed in blue and brown and the line of the measurement in purple.

If I have a graph with only one limit, that limit is displayed in blue and the line of the measurement is displayed in brown. This leads to visual confusion, as the limit was previously displayed in brown.

The idea is to assign a fixed colour to line of the measured value.