1. Change 'spacing: 0' to 'spacing: units.smallSpacing' in /usr/share/plasma/plasmoids/org.kde.plasma.private.systemtray/contents/ui/main.qml - what this patch is basically doing anyway
2. Reload plasmashell and add a System Tray Plasmoid if one isn't already added
Before:
Breeze:
{F8107342}
{F8107345}
Feren OS's Plasma Theme:
{F8107347}
{F8107349}
Reactionary (3rd-party theme example):
{F8107350}
{F8107351}
After:
Breeze:
{F8107355}
{F8107356}
Feren OS's Plasma Theme:
{F8107357}
{F8107358}
Reactionary (3rd-party theme example):
{F8107361}
{F8107364}
Alternative After (Units.smallSpacing / 2):
Breeze:
{F8107366}
{F8107369}
Feren OS's Plasma Theme:
{F8107374}
{F8107377}
Reactionary (3rd-party theme example):
{F8107379}
{F8107380}
(ignore the blur on the tray expand button, that's unrelated to this patch)