exp show: Sort deps columns.

Closes #7312

dvc/commands/experiments/show.py

@@ -49,7 +49,7 @@ def _collect_names(all_experiments, **kwargs):
             for dep_name in exp.get("deps", {}):
                 deps_names.add(dep_name)
 
-    return metric_names, param_names, deps_names
+    return metric_names, param_names, sorted(deps_names)
 
 
 experiment_types = {

tests/func/experiments/test_show.py

@@ -660,3 +660,21 @@ def test_show_outs(tmp_dir, dvc, scm):
             "nfiles": None,
         }
     }
+
+
+def test_show_sorted_deps(tmp_dir, dvc, scm, capsys):
+    tmp_dir.gen("a", "a")
+    tmp_dir.gen("b", "b")
+    tmp_dir.gen("c", "c")
+    tmp_dir.gen("z", "z")
+
+    dvc.run(
+        cmd="echo foo",
+        name="deps",
+        deps=["a", "b", "z", "c"],
+    )
+
+    capsys.readouterr()
+    assert main(["exp", "show", "--csv"]) == 0
+    cap = capsys.readouterr()
+    assert "a,b,c,z" in cap.out