UserService: use the UserService instead of calling sqlstore directly (#55745)

* UserService: update callers to use the UserService instead of calling sqlstore directly

There is one major change hiding in this PR. UserService.Delete originally called a number of services to delete user-related records. I moved everything except the actual call to the user table, and moved those into the API. This was done to avoid dependencies cycles; many of our services depend on the user service, so the user service itself should have as few dependencies as possible.

pkg/services/user/usertest/fake.go

@@ -13,6 +13,8 @@ type FakeUserService struct {
 	ExpectedSetUsingOrgError error
 	ExpectedSearchUsers      user.SearchUserQueryResult
 	ExpectedUSerProfileDTO   user.UserProfileDTO
+
+	GetSignedInUserFn func(ctx context.Context, query *user.GetSignedInUserQuery) (*user.SignedInUser, error)
 }
 
 func NewUserServiceFake() *FakeUserService {
@@ -60,6 +62,9 @@ func (f *FakeUserService) GetSignedInUserWithCacheCtx(ctx context.Context, query
 }
 
 func (f *FakeUserService) GetSignedInUser(ctx context.Context, query *user.GetSignedInUserQuery) (*user.SignedInUser, error) {
+	if f.GetSignedInUserFn != nil {
+		return f.GetSignedInUserFn(ctx, query)
+	}
 	if f.ExpectedSignedInUser == nil {
 		return &user.SignedInUser{}, f.ExpectedError
 	}