fix #19900 #19888 加班申请单、用车申请单

lib/shared/widgets/bill_status_bar.dart

@@ -79,6 +79,7 @@ class BillStatusBar {
   bool get showCancelSubmit => _approvalStatus == 'SHCOUNT1';
 
   bool get showReturn {
+    if (onReturn == null) return false;
     final s = _approvalStatus;
     return (s == 'SHCOUNT4' || s == 'SHCOUNT6') && !_isClosed && !_isTransferred;
   }
@@ -187,7 +188,7 @@ class BillStatusBar {
                 text: _editLabel(l10n),
                 size: TDButtonSize.medium,
                 type: TDButtonType.outline,
-                shape: TDButtonShape.rectangle,
+                shape: TDButtonShape.round,
                 theme: TDButtonTheme.primary,
                 onTap: onEdit,
               ),
@@ -202,7 +203,7 @@ class BillStatusBar {
                 text: _submitLabel(l10n),
                 size: TDButtonSize.medium,
                 type: TDButtonType.fill,
-                shape: TDButtonShape.rectangle,
+                shape: TDButtonShape.round,
                 theme: TDButtonTheme.primary,
                 onTap: onSubmit,
               ),
@@ -214,7 +215,7 @@ class BillStatusBar {
                 text: _cancelSubmitLabel(l10n),
                 size: TDButtonSize.medium,
                 type: TDButtonType.fill,
-                shape: TDButtonShape.rectangle,
+                shape: TDButtonShape.round,
                 theme: TDButtonTheme.danger,
                 onTap: onCancelSubmit,
               ),
@@ -228,7 +229,7 @@ class BillStatusBar {
                 text: _returnLabel(l10n),
                 size: TDButtonSize.medium,
                 type: TDButtonType.fill,
-                shape: TDButtonShape.rectangle,
+                shape: TDButtonShape.round,
                 theme: TDButtonTheme.primary,
                 onTap: onReturn,
               ),