Enable SyncAuthorizedEntries by default

[azdagron]

Using SyncAuthorizedEntries is currently experimental. Consider turning it on by default in a minor release boundary.

[rturner3]

Our plan to enable this by default is to change the value of experimental.use_sync_authorized_entries in SPIRE Agent from false to true in 1.12.0 and deprecate this config field. In 1.13.0, we plan to remove the experimental.use_sync_authorized_entries config field if there are no major issues reported with this feature.