simplify: dedupe boilerplate and remove dead code across all layers

lib/view/pages/files/files_upload_dialog.dart

@@ -62,12 +62,14 @@ class _FilesUploadDialogState extends State<FilesUploadDialog> {
     );
   }
 
+  void _resetProgress() {
+    _isUploading = false;
+    _overallProgressValue = 0.0;
+    _infoText = '';
+  }
+
   void _showUploadError(String message) {
-    setState(() {
-      _isUploading = false;
-      _overallProgressValue = 0.0;
-      _infoText = '';
-    });
+    setState(_resetProgress);
     InfoDialog.show(
       context,
       message,
@@ -157,9 +159,7 @@ class _FilesUploadDialogState extends State<FilesUploadDialog> {
 
         if (replaceFiles != true) {
           setState(() {
-            _isUploading = false;
-            _overallProgressValue = 0.0;
-            _infoText = '';
+            _resetProgress();
             for (var element in conflictingFiles) {
               element.isConflicting = true;
             }
@@ -222,11 +222,7 @@ class _FilesUploadDialogState extends State<FilesUploadDialog> {
       }
 
       if (uploadTask.statusCode < 200 || uploadTask.statusCode > 299) {
-        setState(() {
-          _isUploading = false;
-          _overallProgressValue = 0.0;
-          _infoText = '';
-        });
+        setState(_resetProgress);
         if (!mounted) return;
         Navigator.of(context).pop();
         showHttpErrorCode(uploadTask.statusCode);
@@ -235,11 +231,7 @@ class _FilesUploadDialogState extends State<FilesUploadDialog> {
       }
     }
 
-    setState(() {
-      _isUploading = false;
-      _overallProgressValue = 0.0;
-      _infoText = '';
-    });
+    setState(_resetProgress);
     if (!mounted) return;
     Navigator.of(context).pop();
     widget.onUploadFinished(uploadetFilePaths);