fix: use consistent instrument name for soundmeter playback

_getChartConfig used 'soundmeter' but _playFile used 'sound meter',
causing the chart config to never match and sound meter playback
to silently do nothing. Changed _getChartConfig to use 'sound meter'
to match the value from appLocalizations.soundMeter.toLowerCase().

Author: prajakta128

lib/view/logged_data_screen.dart

@@ -330,7 +330,7 @@ class _LoggedDataScreenState extends State<LoggedDataScreen> {
           'xDataColumnIndex': 0,
           'yDataColumnIndex': 2,
         };
-      case 'soundmeter':
+      case 'sound meter':
         return {
           'xAxisLabel': appLocalizations.timeAxisLabel,
           'yAxisLabel': appLocalizations.db,