Fix "Binding on indicator is not deferred"

Fixes:
    "Binding on indicator is not deferred as requested by the
     DeferredPropertyNames class info because it constitutes a group
     property."

This fixes one instance of the Binding not deferred warning.
It also shows better form - where you should not infer the
implementation of a QML Item from another QML file that uses it. Alter
internals using toplevel properties instead.

Author: keithel-qt

resources/BaseComponents/SmallCheckBox.qml

@@ -9,6 +9,9 @@ import QtQuick.Templates as T
 T.CheckBox {
     id: control
 
+    property alias indicatorHeight: control.indicator.height
+    property alias indicatorWidth: control.indicator.width
+
     spacing: 2
     implicitWidth: Math.max(implicitBackgroundWidth + leftInset + rightInset, implicitContentWidth + leftPadding + rightPadding)
     implicitHeight: Math.max(implicitBackgroundHeight + topInset + bottomInset, implicitContentHeight + topPadding + bottomPadding, implicitIndicatorHeight + topPadding + bottomPadding)

resources/ObservationTabComponents/ObservationFilterColumn.qml

@@ -18,8 +18,8 @@ ColumnLayout {
         model: codes
 
         SmallCheckBox {
-            indicator.width: 15
-            indicator.height: 15
+            indicatorWidth: 15
+            indicatorHeight: 15
             spacing: 2
             padding: 2
             verticalPadding: 0.2