Webhooks table should use table skeleton rather than spinner to denote loading

[dibbles]

When the webhooks table is loading a spinner indicates the page is loading, one could reasonably argue that this should instead be rendering the page but with a carbon component table skeleton.

http://react.carbondesignsystem.com/?selectedKind=DataTableSkeleton&selectedStory=default&full=0&addons=1&stories=1&panelRight=0&addonPanel=storybook%2Factions%2Factions-panel

[carlos-logro]

/assign

[carlos-logro]

/close

[tekton-robot]

@carlos-logro: Closing this issue.

In response to this:

/close

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