Wrong StoreUsageLimit computed at startup

When ActiveMQ starts, it tries to adjust its store limits based on the total available space on the disk. However, if the store is not empty, the current Usage is not taken into account.

Scenario
Store Limit = 20 Go, disk Size = 25 Go, current Store Usage = 15 Go

When restarting ActiveMQ, available disk space is 25 -15 = 10 Go, and the broker automatically resize the store limit from 20 to 10 Go. However, the store is already 15 Go, and thus effectively full (store usage = 150% reported in the console).

Starting logs:

WARN | Store limit is 20240 mb (current store usage is 0 mb). The data directory: (...)\data\kahaDB only has 12387 mb of usable space. - resetting to maximum available disk space: 12387 mb

Logs report a current usage of 0 Mb whereas there is more than 10 Go of data in the store. When connecting a debugger to ActiveMQ, I noticed that the current store usage is computed before the persistence adapter is configured (this is done by the post construct in XBeanBrokerService#ensureSystemUsageHasStore(), and thus always report '0'.

Tested on 5.14.1, but the same behavior was already noticed on 5.12.x and 5.13.x versions