[2.3.0] Checkmk Werk 16682 created: Ruleset API: Fix migration with scaling of SimpleLevels

[//]: # (werk v2) # Ruleset API: Fix migration with scaling of SimpleLevels key | value ---------- | --- date | 2024-04-17T11:19:36+00:00 version | 2.3.0b6 class | fix edition | cre component | checks level | 1 compatible | no This change is relevant to plugin developers The migration helper functions `migrate_to_integer_simple_levels` and `migrate_to_float_simple_levels` for `SimpleLevels` currently apply the scaling factor (if given) every time the migration is run, meaning also to the already migrated value. This means any rule where these helpers are used with a scaling factor will have incorrect values and will have to be manually corrected. No shipped rules are affected by this.