[Offers] Total offers in subjects are calculated for without role separation

[Roman-Peretiatko]

Description: Total offers in subjects are not calculated propperly. It should be calculated for scpecific subject and separated by roles. (look into hooks in Offer model)

Reproducible: always.

Preconditions:
The user is logged in.

Steps to reproduce:

1. Create an offer with specified subject

Actual result:
Total offers calculated for all roles

Expected result:
Total offers must be calculated separeated for roles