Add a toast for pasting blocks (and ensure it is read out by screen readers)

[jversloot]

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Problem

Currently, when pasting a block, there is no auditory feedback indicating that the block has been successfully pasted except the rereading of the block pasted. I believe work is being done to ensure toasts are read out for screen readers (if not then that is a separate bug I can log), but there is currently no toast for a pasted block, just a copied block.

Request

Suggesting to implement a "Paste Toast" notification. This toast would appear briefly after a block is pasted, confirming that the block has been successfully placed.
The toast could also provide additional context, such as the position of the pasted block relative to other blocks (e.g., "Block pasted below Block A"?).

Alternatives considered

An alternative would be to rely on the built-in toast notifications or alerts provided by screen readers, but this approach has proven to be inconsistent across different screen readers.
Another alternative is to use the block readout when the block is pasted as an indicator of when the block is pasted but the readout can be confusing and verbose especially given that the block that was copied would be the same.

Additional context

No response

[maribethb]

In the user testing, people liked the sound effects so I think instead of adding a toast, we should add a sound effect when a block is added to the workspace. see #778