"Duplicate this block" context menu option

Often times it's wanted to duplicate a single stack block already present on the workspace; for that purpose, there should be a context menu option, which would act as the normal Duplicate option but only duplicate the stack block (and attached reporter blocks) that was clicked - not any blocks below the stack clicked block.

This option is quicker than moving the mouse to the flyout and scrolling it until the wanted block is found, and cleaner (as well as quicker) than separating the blocks below the wanted block, duplicating it, then putting the separated blocks back together.

For example, right-clicking the "glide" block in the image below and selecting "Duplicate this block"...

...would duplicate the "glide secs" block (and attach it to the cursor), including the reporter blocks like "y position" and "pick random", but not the "start sound" block (or any blocks below the glie block).

No files or tests are named. Start by locating the existing Duplicate context-menu option and its block-selection behavior, then compare it with the requested single-stack-block behavior. Done means a clicked block can be duplicated with its attached reporter blocks while excluding blocks below it, with the duplicate attached to the cursor.