A signal strength of 14 will detect " Mobs and players teleporting or spawning", as per the 23w12a changelogs. However, when a player respawns a skulk sensor will not activate.
Pictured below is me respawning after falling into the void, as you can see in the image being respawned its not being picked up by the skulk sensor.
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It seems that the sculk sensor now outputs a signal strength of 2 when players respawn (at least in singleplayer), but this is still not the expected result of 14.