dolphinnavigatorswidgetaction: show focus indicator in split mode

This commit uses KUrlNavigator focus indicator to show sufficiently which panel (left or right) is currently active in split mode.

This MR is based on KIO changes in https://invent.kde.org/frameworks/kio/-/merge_requests/2054

See discussion in MR: !1076 (comment 1334290), see https://invent.kde.org/frameworks/kio/-/merge_requests/2058

@teams/vdg

![Screenshot_20251117_232634.png](/uploads/2999f35fdc1c6dd359621c60d23460f2/Screenshot_20251117_232634.png){width=849 height=313}

![Screenshot_20251117_232704.png](/uploads/bd7b75f9159ab533b8e446781233e027/Screenshot_20251117_232704.png){width=849 height=313}

![Screenshot_20251117_232740.png](/uploads/e07153c1e9ae162ebc0ff3f09df1ac34/Screenshot_20251117_232740.png){width=849 height=313}

![Screenshot_20251117_232752.png](/uploads/ececd4c70c0e1f67145e2486d1cf21f2/Screenshot_20251117_232752.png){width=849 height=313}

@teams/vdg

BUG: 150718

BUG: 428440

0 files changed, 0 insertions, 0 deletions