test(reporting): compile instrumented SettingsScreen test with onReportProblem

The #32/#33 change added a required onReportProblem parameter to SettingsScreen
but left the existing instrumented SettingsScreenTest calling the old signature,
so :app:compileDebugAndroidTestKotlin failed in every E2E job (the local fast
gate never compiles the androidTest variant). Pass onReportProblem = {} in the
test. Verified with :app:compileDebugAndroidTestKotlin on JDK 21.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/androidTest/kotlin/org/libremail/ui/settings/SettingsScreenTest.kt

@@ -39,7 +39,13 @@ class SettingsScreenTest {
 
         composeTestRule.setContent {
             LibreMailTheme(darkTheme = false, dynamicColor = false) {
-                SettingsScreen(onAddAccount = {}, onOpenAccount = {}, onSelectTab = {}, viewModel = viewModel)
+                SettingsScreen(
+                    onAddAccount = {},
+                    onOpenAccount = {},
+                    onSelectTab = {},
+                    onReportProblem = {},
+                    viewModel = viewModel,
+                )
             }
         }