title: Chart.js sum y values depending on time unit
body: <p>New to Chart.js, I was wondering if there is a built in method to sum y values depending on time unit.<br />
  Asking here after a lot of search in the docs.</p>
  <p>For now, the bar for March shows 20 and the bar for June shows 10.<br />
  I want to have 25 for March and 15 for June, so to sum y for the same month.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>const ctx = document.getElementById("tests-chart")
  const testsChart = new Chart(ctx, {
      type: "bar",
      data: {
          datasets: [
              {
                  label: 'Dataset 1',
                  data: [
                      { x: "24/03/2022", y: 20 },
                      { x: "25/03/2022", y: 5 },
                      { x: "24/06/2022", y: 10 },
                      { x: "25/06/2022", y: 5 },
                  ],
                  backgroundColor: 'rgb(255, 99, 132)',
                },
          ],
      },
      options: {
          scales: {
              x: {
                  type: "time",
                  time: {
                      parser: "dd/MM/yyyy",
                      unit: "month",
                      // Luxon format string
                      tooltipFormat: "MM",
                      round: 'month'
                  },
              },
          },
      },
  })</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.1/chart.min.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdn.jsdelivr.net/npm/luxon@2.3.1/build/global/luxon.min.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdn.jsdelivr.net/npm/chartjs-adapter-luxon@1.1.0/dist/chartjs-adapter-luxon.min.js"&gt;&lt;/script&gt;
  &lt;div&gt;
    &lt;canvas id="tests-chart"&gt;&lt;/canvas&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>