[client] Fold the scheme case here too, like util does (review item 6)

profilemanager.SameServiceURL compared the scheme with ==, util.SameServiceURL
with EqualFold. No observable difference — net/url lowercases the scheme when
it parses, and both functions take parsed URLs — but two functions of the same
name with two different rules is a trap for whoever reads one and assumes the
other.

client/internal/profilemanager/config.go

@@ -1009,7 +1009,7 @@ func SameServiceURL(a, b *url.URL) bool {
 		return a == b
 	}
 
-	return a.Scheme == b.Scheme &&
+	return strings.EqualFold(a.Scheme, b.Scheme) &&
 		strings.EqualFold(a.Hostname(), b.Hostname()) &&
 		util.ServiceURLPort(a) == util.ServiceURLPort(b)
 }