diagnostics: Show app name and fallback to app id if not exist

Tests performed:
- The diagnostics app page and individual app diagnostics pages have
app names.
- When the app name is missing (the apache app), app id is shown instead.

Signed-off-by: Veiko Aasa <veiko17@disroot.org>

plinth/modules/diagnostics/__init__.py

@@ -112,7 +112,7 @@ def run_on_all_enabled_modules():
             continue
 
         apps.append((app.app_id, app))
-        app_name = app.info.name or _('None')
+        app_name = app.info.name or app.app_id
         current_results['results'][app.app_id] = {'name': app_name}
 
     current_results['apps'] = apps

plinth/modules/diagnostics/templates/diagnostics_app.html

@@ -9,7 +9,7 @@
 
   <h2>{% trans "Diagnostic Results" %}</h2>
 
-  <h3>{% blocktrans %}App: {{ app_id }}{% endblocktrans %}</h3>
+  <h3>{% blocktrans %}App: {{ app_name }}{% endblocktrans %}</h3>
 
   {% if results %}
     {% include "diagnostics_results.html" with results=results %}

plinth/modules/diagnostics/views.py

@@ -38,6 +38,7 @@ def diagnose_app(request, app_id):
         app = App.get(app_id)
     except KeyError:
         raise Http404('App does not exist')
+    app_name = app.info.name or app_id
 
     diagnosis = None
     diagnosis_exception = None
@@ -51,7 +52,7 @@ def diagnose_app(request, app_id):
     return TemplateResponse(
         request, 'diagnostics_app.html', {
             'title': _('Diagnostic Test'),
-            'app_id': app_id,
+            'app_name': app_name,
             'results': diagnosis,
             'exception': diagnosis_exception,
         })