introduce the showLoadingSpinner prop in TableView.svelte

[abab-dev]

Fixes #4169

Introduce the new prop showLoadingSpinner with default value true.
Whenever we do not want to show the spinner,
we will set it to false and spinner will not be shown.

Screenshots

output.mp4

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[seancolsen]

Thanks @abab-dev but I had to changes the logic a bit in 36e8080 since w still want to show the loading spinner in the table widget before any of the columns have loaded.