Color Picker: Allow to override `mode` and `width` values for Iris via wpColorPicker options.

props jtsternberg.
fixes #30182.
Built from https://develop.svn.wordpress.org/trunk@30330


git-svn-id: http://core.svn.wordpress.org/trunk@30329 1a063a9b-81f0-0310-95a4-ce76da25c4cd