Revert nuxeo-checkmark to opacity of 1.0

nuxeo-checkmark seen when selecting a row from a nuxeo-data-table has an opacity of 0.7, causing its color to be faded in comparison to elements of the same color code (for example, nuxeo-document-create-button).

Steps to Reproduce:

1. From a Folderish Document view tab, select one or more children Documents while in Table View.

Expected behavior: nuxeo-checkmark has opacity of 1.0 (equal visible color to nuxeo-document-create)

Actual behavior: nuxeo-checkmark has opacity of 0.7 and is visibly faded in comparison to like-color elements.