"on pin pulse" block and variables as inputs

[microbit-carlos]

A continuation of the discussion from:

• Bring event block after "on-start" #5752 (comment)

With the latest pin changes (thanks @sae220 and @riknoll!), we have the "on pin pulse" block which can take an input to indicate which pin to select.

With the shadow block we can select any available pin:

We can also add a "digital pin" or "analog pin" block as an input:

But when adding a variable we encounter a warning, for the reasons listed in #5752 (comment):

So, it's not too clear what might be the advantage to have a shadow block in this block, if dropping a variable cannot work and dropping a "digital pin" or "analog" pin block does not offer any advantages over the shadow block itself.

To avoid confusion with the variable warning perhaps we should revert this block to simply have a dropdown like in Makecode v6?

[riknoll]

yeah, i think it makes sense to revert this single block. i'll open a PR