We control whether online migrations run or not via a new parameter
EnableOnlineDataMigrations. The online data migrations get
automatically disabled for the main upgrade phase, and automatically
enabled on upgrade converge.
This means that if no manual override is done, the migrations will run
on `upgrade converge` automatically. However, user is still able to
override the EnableOnlineDataMigrations, to e.g. completely opt out of
running the migrations automatically, if they wish to run them by
hand.
This patch is a "spiritual backport" of change
I35c8d9985df21b3084fba558687e1f408e5a0878, which is not backportable
further back than Rocky.
Change-Id: Ife468bc86b4b2c415783f37ff8ef2f90a4c0e465
Partial-Bug: #1793332
218ff2a50e