fix some null check errors in IT

lib/pangea/choreographer/controllers/choreographer.dart

@@ -116,10 +116,9 @@ class Choreographer {
     // we've got a rather elaborate method of updating tokens after matches are accepted
     // so we need to check if the reconstructed text matches the current text
     // if not, let's get the tokens again and log an error
-    final reconstructedText =
-        PangeaToken.reconstructText(igc.igcTextData!.tokens);
     if (igc.igcTextData?.tokens != null &&
-        reconstructedText.trim() != currentText.trim()) {
+        PangeaToken.reconstructText(igc.igcTextData!.tokens).trim() !=
+            currentText.trim()) {
       if (kDebugMode) {
         PangeaToken.reconstructText(
           igc.igcTextData!.tokens,

lib/pangea/choreographer/controllers/it_controller.dart

@@ -146,6 +146,8 @@ class ITController {
         //     ? _customInputTranslation(currentText)
         //     : _systemChoiceTranslation(translationId));
 
+        if (sourceText == null) return;
+
         if (res.goldContinuances != null && res.goldContinuances!.isNotEmpty) {
           goldRouteTracker = GoldRouteTracker(
             res.goldContinuances!,