(core) Improve printing of tables, fix printing of charts, add a browser test.

Summary:
- Include column headers on each page for printing tables.
- Avoid page-breaks inside rows or cards of a card-list.
- Fix printing of charts that did not show up at all before.
- Add a browser test, not great, but somewhat functional.

Test Plan: New test, plus tested manually. Column headers work on Chrome and Firefox (not Safari).

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2636

app/client/components/Printing.css

@@ -15,6 +15,9 @@
   .print-widget {
     margin: 0px !important;
   }
+  .print-row {
+    break-inside: avoid;
+  }
 
   .print-widget .viewsection_title {
     display: none !important;
@@ -35,13 +38,6 @@
     position: relative !important;
     height: max-content !important;
     overflow: visible !important;
-    border-top: 1px solid var(--grist-color-dark-grey);
-    border-left: 1px solid var(--grist-color-dark-grey);
-  }
-
-  .print-widget .gridview_data_scroll {
-    position: relative !important;
-    height: max-content !important;
   }
 
   .print-widget .scrolly_outer {
@@ -51,6 +47,21 @@
   .print-widget .custom_view {
     height: calc(100vh - 24px);
   }
+
+  .ui-resizable-handle {
+    display: none !important;
+  }
+}
+
+/*
+ * The chart div needs to be measured before its relayout() call, and "@media print" is not in
+ * effect for that measurement, so we temporarily resize the chart for all @media, to a plausible
+ * size for printing.
+ */
+.print-widget .chart_container {
+  width: 6.5in !important;
+  height: 6.5in !important;
+  overflow: visible !important;
 }
 
 @media not print {