remember "Show Totals Row" preference under each report

The new Show Totals Row feature is very valuable. Currently when you click away from a report and reopen it a few seconds or minutes later:

• Got: you have to click "Show Totals Row" again (and again...) to see the Totals row.
• Expected: when it was clicked under a particular report, the preference should be remembered and restored on further reloads.

(it is quite a common use case when looking at the "Totals" metric you actually compare this value to other "Totals" or other metrics in different reports.)

refs https://github.com/matomo-org/matomo/issues/5386