(core) Fix issue that ints would be imported with a trailing ".0" from Google Sheets.

Summary:
Whole numbers, when imported from Excel into a Text column show up
without decimals (e.g. "300"), but when imported from Google Sheets show
up with decimals (e.g. "300.0"). The decimals are hard for end-users to
remove. Fix by treating whole numbers consistently as ints.

Test Plan: Added a fixture reproducing the issue, and a test case.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D3800

sandbox/grist/parse_data.py

@@ -195,6 +195,12 @@ class ColumnConverter(object):
     # For some reason, we get 'str' type rather than 'unicode' for empty strings.
     # Correct this, since all text should be unicode.
     value = u"" if value == "" else value
+
+    # Integer values sometimes show up as ints (from Excel), sometimes as floats (from Google).
+    # Make them consistently ints; this avoid addition of ".0" suffix when converting to text.
+    if type(value) == float and value.is_integer():
+      value = int(value)
+
     try:
       conv = self._converter.convert(value)
       self._converted_values.append(conv)