paramètres: fix logs Copier button scrolling out of view on horizontal scroll

Wrap .log-output and the copy button in a .log-output-wrapper div
with position:relative, so the button sits outside the overflow-x:auto
scroll container and stays fixed at the top-right corner.

app/public/assets/css/system.css

@@ -306,6 +306,9 @@
 	line-height: 1.55;
 	max-height: 62vh;
 	overflow-y: auto;
+}
+
+.log-output-wrapper {
 	position: relative;
 }
 .log-line {