Update heatmap (#1162)

Subset genes specified in `gene_order` to ones for which a model has
been fit.

src/cellrank/pl/_heatmap.py

@@ -362,6 +362,7 @@ def _(gene_order: Optional[Sequence[str]] = None) -> Tuple[List[plt.Figure], pd.
 
             if not cluster_genes:
                 if gene_order is not None:
+                    gene_order = [gene for gene in gene_order if gene in df.index]
                     df = df.loc[gene_order]
                 else:
                     max_sort = np.argsort(np.argmax(df.apply(_min_max_scale, axis=1).values, axis=1))