Default system dashboard respect stop timestamp when using a custom timerange

__Steps to reproduce:__
List the minimal actions needed to reproduce the behavior.

1. In the web interface: Boards > Create Dashboard > From a Template > System > Create Dashboard
2. Configure telegraf to send system data into a bucket
3. View the data in the default system dashboard
4. Select a custom time range, use a stop time from the past
5. The cells/graphs in the dashboard don't respect the stop time

__Expected behavior:__
The graph should stop at the stop time rather than the present time

__Actual behavior:__
The graph always stops at the current time

__Fix__
Swapping line 2 in each of the cells from
|> range(start: v.timeRangeStart)
to
|> range(start: v.timeRangeStart, stop: v.timeRangeStop)
fixes this, I'd like to have opened a PR as this is a small change but I'm struggling to find where the default dashboards are imported from.

The issue identifies the default System dashboard and the Flux range lines in its cells, but not their source files. First locate where the System template is imported or defined, then inspect each cell's query and verify that selecting a past custom stop time ends the graphs at that time.

Written by the indexing model from the issue text.