positioning attributes for label & auto sizing for shapes don't work for style sequence_diagram

[hrajpal96]

There are two issues currently: -

1. Positioning of label attribute doesn't work for any block in sequence diagram mode.
2. Auto sizing of block doesn't work while using both label and icon in the same block.

[alixander]

Example for 1:

https://play.d2lang.com/?script=Ks5ILEi1UihOLSxNzUtOjU_JTEwvSszl4qpQ0LVTqOSq0MtJTErN0ctLTSyyUijJL9DNSU0r4QIEAAD__w%3D%3D&

[alixander]

@hrajpal96 can you give an example for 2?