ListSelector restricted to list type objects

[maximlt]

Fixes #527

I chose to raise a ValueError when the type is not a list since raising ValueError seems to be what param does in this case. The tests used to catch TypeErrors in some occasions because param was trying to iterate over non iterables.

[codecov-commenter]

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[philippjfr]

We need to be consistent about ValueError and TypeError but in this case this is more consistent because it matches what param.List raises when given the wrong type.