ui: remove percentage axis units

The enum value AxisUnits.Percentage is presently unused.  This removes
it, along with dead code to calculate axis ticks for percentage values.
If it comes up in the future that we need it, we can add it back in.

pkg/ui/src/views/cluster/util/graphs.ts

@@ -204,20 +204,6 @@ function ComputeDurationAxisDomain(
   return axisDomain;
 }
 
-const percentIncrementTable = [0.25, 0.5, 0.75, 1.0];
-
-function ComputePercentageAxisDomain(
-  min: number, max: number,
-) {
-  const range = max - min;
-  const increment = computeNormalizedIncrement(range, percentIncrementTable);
-  const axisDomain = new AxisDomain(min, max, increment);
-  axisDomain.label = "percentage";
-  axisDomain.tickFormat = d3.format(".0%");
-  axisDomain.guideFormat = d3.format(".2%");
-  return axisDomain;
-}
-
 const timeIncrementDurations = [
   moment.duration(1, "m"),
   moment.duration(5, "m"),
@@ -327,9 +313,6 @@ function ProcessDataPoints(
     case AxisUnits.Duration:
       yAxisDomain = ComputeDurationAxisDomain(yExtent[0], yExtent[1]);
       break;
-    case AxisUnits.Percentage:
-      yAxisDomain = ComputePercentageAxisDomain(yExtent[0], yExtent[1]);
-      break;
     default:
       yAxisDomain = ComputeCountAxisDomain(yExtent[0], yExtent[1]);
   }

pkg/ui/src/views/shared/components/metricQuery/index.tsx

@@ -41,10 +41,6 @@ export enum AxisUnits {
    * Units are durations expressed in nanoseconds.
    */
   Duration,
-  /**
-   * Units are percentages expressed as fractional values of 1 (1.0 = 100%).
-   */
-  Percentage,
 }
 
 /**