Setting the collapsedIcon option with false

Expected: data-collapsed-icon="false"

Test:

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1. Get the class names of the each example
2 - 1. Set the collapsedIcon option of the test with false
2 - 2. Set the collapsedIcon option of the test with "false"
2 - 3. Set the collapsedIcon option of the test with "plus"
3. Get the class names of the each example again