Using static width for color-picker-cell
Fixes content proxy performance on selects

Before, the content proxy would re-sort and re-filter
its content after any change to its content's labels
(e.g. if something is added/deleted to the content, or
if a label changed). This ultimately lead to O(n^2 * log(n))
performance for adding n items. This change makes it so that
the filteredContent and sortedFilteredContent properties are
updated in a debounced way which means that we should basically
have O(n * log(n)) performance (only the last sort matters).
Fixes last commit which had small error
Make select debounce immediate
The `SelectComponent` doesn't block page rendering with big collection.

The dropdown observes any changes to the `optionsLabelPath`. This can be
pretty slow with a big collection (several seconds) and it would get
computed even if the dropdown would never be opened.

This commit allows to do the computation only when the dropdown is
actually opened.

This is not a perfect solution as the slowness will still appear the
first time the dropdown is opened ( or if the content changes ).

Code by @bigsley and @cyril-sf