Storage_server json inhibits ert from plotting after error encountered

[andreas-el]

Whenever Ert encounters an error during plotting, you cannot plot storage content anymore. Ert will just hang.

---

Reproduce by: First run poly-example to have something to plot.

Add some error, for example adding raise ValueError() at the bottom of observations_for_key in plot_api.py

                all_observations = pd.concat(
                    [all_observations, pd.DataFrame(data_struct)]
                )
        raise ValueError()
        return all_observations.T

Run ert and have the error raised when trying to plot. Revert code snippet, and observe that you cannot plot content anymore. Ert will just hang.

I've diffed the output and found this;

diff --color -Nau lol/poly_example/storage/storage_server.json test-data/poly_example/storage/storage_server.json
--- lol/poly_example/storage/storage_server.json	1970-01-01 01:00:00
+++ test-data/poly_example/storage/storage_server.json	2024-08-13 13:49:49
@@ -0,0 +1,8 @@
+{
+    "urls": [
+        "http://127.0.0.1:51834",
+        "http://AC-WR4GDXT41X:51834",
+        "http://AC-WR4GDXT41X:51834"
+    ],
+    "authtoken": "<token>"
+}
\ No newline at end of file

Removing that json file seems to unclog plotting again.