Fix : Block Inserter Search Infinity Spinner

[Vrishabhsk]

What?

• https://core.trac.wordpress.org/ticket/62796

Why?

• When the user is offline, the search prodiuces a 500 error code, the Infinity Spinner is not hidden
• The Spinner should be hidden once the request fails, and should render the relevant placeholder

How?

• Return empty array in the place of blocks in the error part of the trycatch block

Screenshots or screencast

Before	After

[github-actions]

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Co-authored-by: Vrishabhsk <[email protected]>

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