[FIX] Charts: Fix tooltip value when data is zero

Following a refactoring of the charts, the tooltip would not display the
data value when the data equalled zero.

How to reproduce:
- generate a line graph such that one of the dataset points is 0
- Hover the said data point

-> the tooltip will read something along "Series 1:" and no value
afterwards.

Task: 4251681
X-original-commit: ec02c46

src/helpers/figures/charts/chart_ui_common.ts

@@ -157,7 +157,7 @@ export function getDefaultChartJsRuntime(
             const xLabel = tooltipItem.dataset?.label || tooltipItem.label;
             // tooltipItem.parsed can be an object or a number for pie charts
             let yLabel = horizontalChart ? tooltipItem.parsed.x : tooltipItem.parsed.y;
-            if (!yLabel) {
+            if (yLabel === undefined || yLabel === null) {
               yLabel = tooltipItem.parsed;
             }
             const toolTipFormat = !format && Math.abs(yLabel) >= 1000 ? "#,##" : format;

tests/figures/chart/chart_plugin.test.ts

@@ -1977,6 +1977,7 @@ describe("Chart design configuration", () => {
       expect(label).toEqual("6,000");
     });
 
+<<<<<<< 18.0
     test.each(["line", "scatter", "combo", "bar"] as const)(
       "%s chart with no title and no legend have the correct padding",
       (chartType) => {
@@ -2050,6 +2051,18 @@ describe("Chart design configuration", () => {
           left: 20,
           right: 20,
         });
+||||||| 890f74235c9acf20fad16c1bfe054bf329a06ada
+=======
+    test.each(["bar", "line"])(
+      "Basic chart tooltip label, zero-values are properly displayed",
+      (chartType) => {
+        setCellContent(model, "A2", "0");
+        createChart(model, { ...defaultChart, type: chartType as "bar" | "line" }, "42");
+        const runtime = model.getters.getChartRuntime("42") as BarChartRuntime;
+        const label = getTooltipLabel(runtime, 0, 0);
+
+        expect(label).toEqual("0");
+>>>>>>> 5d9984709ef8d5f57803fbf1a49c56233990ee1c
       }
     );
   });