Add missing condition for partial index

in `db/structure.sql.

See
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/47193#note_452329021.

db/structure.sql

@@ -22257,7 +22257,7 @@ CREATE INDEX index_users_on_name_trigram ON users USING gin (name gin_trgm_ops);
 
 CREATE INDEX index_users_on_public_email ON users USING btree (public_email) WHERE ((public_email)::text <> ''::text);
 
-CREATE INDEX index_users_on_require_two_factor_authentication_from_group ON users USING btree (require_two_factor_authentication_from_group);
+CREATE INDEX index_users_on_require_two_factor_authentication_from_group ON users USING btree (require_two_factor_authentication_from_group) WHERE (require_two_factor_authentication_from_group = true);
 
 CREATE UNIQUE INDEX index_users_on_reset_password_token ON users USING btree (reset_password_token);