Trace View: Consecutive span colors are similar hue for certain service names

**Steps to reproduce**: Users encountered that for some service names, the Trace View panel algorithm generates consecutive span colors that are similar in hue. The following test is an example of this, where the resulting colors are similar shades of green. ``` it('test similar colors for certain service names', () => { clear(theme); const colorOne = getColorByKey('mockgfeclient', theme); const colorTwo = getColorByKey('telemetry', theme); const colorThree = getColorByKey('mockprokhor', theme); expect(colorOne).toBe('#9AC48A'); // #9AC48A expect(colorTwo).toBe('#629E51'); // #629E51 expect(colorThree).toBe('#B7DBAB'); // #B7DBAB }); ``` The contrast between the colors is above the set threshold (`1.5`): ``` tinycolor.readability(colorOne, colorTwo); // 1.62921488296093 tinycolor.readability(colorTwo, colorThree); // 2.103590206106876 ``` **Actual Result**: For some particular service name, the span color assignment in the Trace View pane (`color-generator.tsx`) generates consecutive colors that are similar in hue (in the example above, green). **Expected Result** Users expected a sequence of colors that also differ in *hue* (green, purple, etc.) not just in *lightness*. **Relevant WCAG Criteria:** [WCAG Criterion](https://www.w3.org/WAI/WCAG21/Understanding/use-of-color.html) We are currently comparing consecutive colors using `tinycolor2/readability`, but this function [measures the contrast](https://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef) between 2 colors (i.e. difference in luminance) to check that two colors are readable against one another.