refactor(themes): drop redundant :has() in dropdown label selector (#8813)

The :has(input[type="checkbox"]) check is redundant. Every <label>
inside .dropdown-menu .item already has a checkbox child (constructed
in main.js), so the selector matches the same set as :not(.noHover)
alone. Removing it makes the rule work in browsers without :has()
support (#6776).

Co-authored-by: Bjørn A. Andersen <polybjorn@users.noreply.github.com>

p/themes/base-theme/frss.css

@@ -409,7 +409,7 @@ input[type="checkbox"] {
 	display: none;
 }
 
-.dropdown-menu .item label:not(.noHover):has(input[type="checkbox"]) {
+.dropdown-menu .item label:not(.noHover) {
 	padding-left: 2.5rem;
 	text-indent: -2.5rem;
 }

p/themes/base-theme/frss.rtl.css

@@ -409,7 +409,7 @@ input[type="checkbox"] {
 	display: none;
 }
 
-.dropdown-menu .item label:not(.noHover):has(input[type="checkbox"]) {
+.dropdown-menu .item label:not(.noHover) {
 	padding-right: 2.5rem;
 	text-indent: -2.5rem;
 }