fix: add matrix parameter spgid to promotion REST calls

[SGrueber]

PR Type

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no API changes)
[ ] Build-related changes
[ ] CI-related changes
[ ] Documentation content changes
[ ] Application / infrastructure changes
[ ] Other:

What Is the Current Behavior?

If a promotion is only valid for registered customers the get /promotions/id REST call ends up with a 404 (not found)

Issue Number: Closes #

What Is the New Behavior?

The matrix parameter spgid is added to the promotions REST call, so the REST call returns data without errors even if the promotion is only valid for registered users.

Steps to repeat

1. Create a promotion in the ICM backoffice that is only valid for registered users, e.g.
   'Registered_1_37_off_for_5816351' inTRONICS Business promotion (1.37 value off for SKU 5816351 for registered users)
2. Clear pagecache
3. Login into the pwa b2b storefront
4. search for product 5816351 and check the network protocol
   -> the get promotions/Registered_1_37_off_for_5816351 call shows a 404 error

Does this PR Introduce a Breaking Change?

[ ] Yes
[x] No

Other Information

AB#80536
AB#80473