fix: sort x values of line plot

src/safeds/data/tabular/plotting/_table_plotter.py

@@ -247,7 +247,8 @@ def line_plot(self, x_name: str, y_name: str) -> Image:
         import polars as pl
 
         grouped = (
-            self._table._lazy_frame.group_by(x_name, maintain_order=True)
+            self._table._lazy_frame.sort(x_name)
+            .group_by(x_name)
             .agg(
                 mean=pl.mean(y_name),
                 count=pl.count(y_name),

tests/safeds/data/tabular/containers/_table/test_plot_lineplot.py

@@ -4,10 +4,22 @@
 from syrupy import SnapshotAssertion
 
 
-def test_should_match_snapshot(snapshot_png_image: SnapshotAssertion) -> None:
-    table = Table({"A": [1, 2, 3], "B": [2, 4, 7]})
-    lineplot = table.plot.line_plot("A", "B")
-    assert lineplot == snapshot_png_image
+@pytest.mark.parametrize(
+    ("table", "x_name", "y_name"),
+    [
+        (Table({"A": [1, 2, 3], "B": [2, 4, 7]}), "A", "B"),
+        (Table({"A": [1, 1, 2, 2], "B": [2, 4, 6, 8]}), "A", "B"),
+        (Table({"A": [2, 1, 3, 3, 1, 2], "B": [6, 2, 5, 5, 4, 8]}), "A", "B"),
+    ],
+    ids=[
+        "functional",
+        "sorted grouped",
+        "unsorted grouped",
+    ],
+)
+def test_should_match_snapshot(table: Table, x_name: str, y_name: str, snapshot_png_image: SnapshotAssertion) -> None:
+    line_plot = table.plot.line_plot(x_name, y_name)
+    assert line_plot == snapshot_png_image
 
 
 @pytest.mark.parametrize(