l10n_fr: fix duplicate "Exporter" action name

On documents, we have an "Export" action for OOoDocument_viewConvertDialog.
When erp5_ods_style is installed, "Export to Spreadsheet" is added as a global
action. Both these actions were translated as "Exporter" in french, which is
confusing and a bit incorrect.
Use a proper, different translation for "Export to Spreadsheet"

bt5/erp5_l10n_fr/MessageTranslationTemplateItem/fr/erp5_ui/translation.po

@@ -5471,7 +5471,7 @@ msgid "Export Terms as PO File"
 msgstr "Exporter les conditions au format PO"
 
 msgid "Export to Spreadsheet"
-msgstr "Exporter"
+msgstr "Exporter en tableur"
 
 msgid "Express Support"
 msgstr "Assistance"