UE: update pdcch config only after mib read - In MR !3929, this change was done to call update_pdcch_config if mac configuration is changed. - Observed that the issue related to RAR after handover if SSB position changes occurs also in develop 2026_w10 where MR !3929 is merged. - update_pdcch_config should be done only after sync obtained. - this fix is similar to the fix in initial commits of MR !3929