Fix fallout from build target rename in signing scripts

We have various problem in the signing scripts I had to fix for the 13.0a3 release to be fixed in a subsequent MR.

added 13.0 stable Build System Signing labels

assigned to @richard

marked this issue as related to #40928 (closed)

marked this issue as related to #40927 (closed)

changed the description

mentioned in merge request !791 (merged)

closed

marked this issue as related to #40965 (closed)

marked this issue as related to #40966 (closed)