Table - Update "Custom row wrapper" example

[mcarrano]

Want to update the Custom row wrapper example for tables so it doesn't get confused with selected rows which have the same styling. It's this example: https://www.patternfly.org/v4/components/table#composable-custom-row-wrapper-header-tooltips--popovers.

A design recommendation can be found here: https://github.com/patternfly/patternfly-design/issues/963#issuecomment-1058397366 This sets a background of pf-color-blue-400 with 50% opacity.