Revert "S68452: Replaced PillPicker with single select ComboBox."

This reverts commit 784f20651a59cfa2356f9cd65a5b734a0e477b2e.
Reapply "S68452: Replaced PillPicker with single select ComboBox."

This reverts commit 500690af95954e669db47fd8475ec05fe1ef2cbd.
S71594: Added PortfolioItemsTreeGridApp