[FIX] web: fix data in view graph for concurrent groupby

- Go to any graph view (i.e. in CRM)
- Change "Group By" 2 times very very quickly
(In Chrome, you can set Throttling to "Slow 3G" in Network tab of devtools)
Data from first groupby will be mixed with data from the second one.

A graph reload is performing the following steps:
  * clean previous data
  * fetch data
  * set data
The issue happens when a second reload is performed while the previous one
has not set its data yet and the cleaning step of the second one is performed
before the setting step of the first one.

The solution will be to ignore the setting step of all previous reloads if
there is a more recent one.

opw-2460145

closes odoo/odoo#75307

Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>