In Zabbix 6.4.1 Custom expression (Type of calculation) doesn't works.
Labels (A,B,C etc) is not in alphabet sort as well.

Steps to reproduce:

1. Create or Edit any action with Custom expression (Type of calculation)
2. Set your Custom expression with Labels
3. Click Add or Save

Result:
Custom expressions saved in not as expected
Set expression: (B or E) and C and D and A
but after Save/Update is changed to:
(A or B) and C and D and E

Expected:
Custom expressions should be saved.