feat(icons): added chart-bell-curve icon (#5128)

* Added icons/chart-distribution.svg

* Added icons/chart-distribution.json

* Update chart-distribution.svg paths for clarity

* Apply suggestion from @jguddas

* feat(groups): added `chart` and `graph` groups

* Update and rename chart-distribution.json to chart-bell-curve.json

* Rename chart-distribution.svg to chart-bell-curve.svg

---------

Co-authored-by: codeiku <pim.nauts@dataiku.com>
Co-authored-by: Jakob Guddas <github@jguddas.de>

icons/chart-bell-curve.json

@@ -0,0 +1,27 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "codeiku",
+    "karsa-mistmere"
+  ],
+  "use-cases": [
+    "Showing normal distributions in statistical analysis tools",
+    "Visualizing probability density in educational materials",
+    "Comparing measurements against a distribution in analytics dashboards"
+  ],
+  "tags": [
+    "$group:chart",
+    "distribution",
+    "normal distribution",
+    "gaussian",
+    "probability",
+    "frequency",
+    "density",
+    "symmetric",
+    "standard deviation"
+  ],
+  "categories": [
+    "charts",
+    "math"
+  ]
+}

icons/chart-bell-curve.svg

@@ -0,0 +1,14 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M3 3v16a2 2 0 0 0 2 2h16" />
+  <path d="M7 16c3.5 0 2.5-10 6-10s2.5 10 6 10" />
+</svg>