Fixes an ordering issue where spec.cephConfig settings failed to apply
because the manager wasn't yet running. Moved the config logic from
postMonStartupActions() to a new postMgrStartupActions() to ensure
the mgr is ready before applying config, allowing successful reconciliation.
Signed-off-by: Patryk Rostkowski <patrostkowski@gmail.com>
(cherry picked from commit 44a2eaf02f)