[v5] Opening a Graph view link with a filter does not apply the filters

When opening a Graph view link like https://lnt.ldionne.com/v5/graph?suite=libcxx&machine=linux-x86_64-20260812&metric=execution_time&test_filter=push_back which contains filters, the filters are shown in the "filter" bar, but they are not applied in the list of benchmarks:

The filters are applied whenever a letter is changed in the filter box.

Also, when changing the filter in the filter box, the total count of tests (e.g. `0 of 30 tests selected`) is not updated, it seems to be tied exclusively to the URL parameters.

Start from the v5 Graph view URL and trace how its suite, machine, metric, and test_filter parameters populate the filter bar and benchmark list. Reproduce the issue with the example link, then verify that filters apply on load and that the selected-test count updates when the filter box changes.

Written by the indexing model from the issue text.