Drop empty-input guards from batch loaders

ANY(@ids) with an empty array is valid in Postgres and
CollectRows already yields an empty slice; the early nil
assignments added noise without changing callers.

Signed-off-by: Cursor Agent <cursoragent@cursor.com>

Co-authored-by: Bryan FRIMIN <bryan@frimin.fr>

pkg/coredata/identity.go

@@ -393,12 +393,6 @@ func (i *Identities) LoadByIDs(
 	conn pg.Querier,
 	identityIDs []gid.GID,
 ) error {
-	if len(identityIDs) == 0 {
-		*i = nil
-
-		return nil
-	}
-
 	q := `
 SELECT
     id,

pkg/coredata/membership_profile.go

@@ -502,12 +502,6 @@ func (p *MembershipProfiles) LoadByOrganizationIDAndUserNames(
 	organizationID gid.GID,
 	userNames []string,
 ) error {
-	if len(userNames) == 0 {
-		*p = nil
-
-		return nil
-	}
-
 	q := `
 SELECT
     p.id,

pkg/coredata/personal_api_key.go

@@ -307,12 +307,6 @@ func (a *PersonalAPIKeys) LoadByIDs(
 	conn pg.Querier,
 	apiKeyIDs []gid.GID,
 ) error {
-	if len(apiKeyIDs) == 0 {
-		*a = nil
-
-		return nil
-	}
-
 	q := `
 SELECT
     id,