keep iconography consistent by reusing already existing icons

main/ui/src/main/java/org/cryptomator/ui/controls/FontAwesome5Icon.java

@@ -39,7 +39,6 @@ public enum FontAwesome5Icon {
 	SPINNER("\uF110"), //
 	SYNC("\uF021"), //
 	TIMES("\uF00D"), //
-	TIMES_CIRCLE("\uF057"), //
 	TRASH("\uF1F8"), //
 	UNLINK("\uf127"), //
 	WRENCH("\uF0AD"), //

main/ui/src/main/resources/fxml/unlock_invalid_mount_point.fxml

@@ -24,7 +24,8 @@
 	<children>
 		<HBox spacing="12" VBox.vgrow="ALWAYS">
 			<StackPane alignment="CENTER" HBox.hgrow="NEVER">
-				<FontAwesome5IconView styleClass="glyph-icon-red" glyph="TIMES_CIRCLE" glyphSize="67"/>
+				<Circle styleClass="glyph-icon-red" radius="24"/>
+				<FontAwesome5IconView styleClass="glyph-icon-white" glyph="TIMES" glyphSize="24"/>
 			</StackPane>
 			<VBox spacing="6" HBox.hgrow="ALWAYS">
 				<Text text="%unlock.error.heading" styleClass="label-large"/>