fix(types): stop the type picker selection refresh loop on Unity 6000.6

[VPDPersonal]

Why. On Unity 6000.6+ the type picker recursed until a StackOverflowException (an Editor crash) when a search shortened the list past the selected row. From 6000.6, RefreshItems reports a selection change for an out-of-range selected id on every call, and the picker answered each change with RefreshItems. PR #317 runs this on 6000.6 and needs this first.

What

• Re-bind only the rows that lose and gain the selection (RefreshItem)
• Test: narrowing the results past the selected row
• Test: a selected folder shows its opened icon and closes after

Verification

• Headless repro (reflection, no window), 6000.7.0a3, old code → Editor crash (SIGILL, stack guard)
• Same repro with the fix → passes on 6000.0.64f1, 6000.4.0f1, 6000.7.0a3
• TypeSelectorViewTests need a window: they cannot run with -nographics, so CI checks them

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