fix(tree): parent item behavior of single, children, and multichildren selection modes

[SkyeSeitz]

Actual Behavior

There are a few additional bug fixes needed on the recent adjustments to Tree's selection of parent category w/out selecting children #6926

1. Hit target to expand parent Tree Item does not include icon + text area
2. Parent Tree Items with decedents are selectable in single, children, and childrenmulti selection modes

Expected Behavior

1. Hit target to expand parent Tree Item includes icon + text area
2. Parent Tree Items with decedents are not selectable in single, children, and multichildren selection modes

link to mock ups

Reproduction Sample

https://esri.github.io/calcite-components/?path=/story/components-tree--simple&knob-checked=true&knob-disabled=true&knob-filterEnabled=true&knob-intl-deselect=Deselect&knob-intl-loading=Loading&knob-intl-select=Select&knob-label=Checkbox&knob-loading=true&knob-scale=m&knob-selectable=true&knob-selected=true&knob-thumbnail-position=block-start

Reproduction Steps

Open Tree samples in Story book and click on parents of the mentioned selection modes.

Reproduction Version

v1.3.1

Relevant Info

Related Issues: #6912, #6444, #6509

Regression?

No response

Priority impact

p2 - want for current milestone

Impact

Resolving this bug fix will allow us to move forward on related enhancements & bug fixes to List #6544

Esri team

Calcite (design)

[SkyeSeitz]

cc @geospatialem @ashetland