chore: better BC/FC layer for deprecated `Command::$defaultName`

[chalasr]

Q	A
Branch?	2.6
Tickets	-
License	MIT
Doc PR	-

Command::setDescription() method calls can also be removed once Symfony 6.1+ is required

[KDederichs]

Just pitching in to say that we had a discussion about the same thing in my original PR which got voted against because of deprecation notifications: https://github.com/api-platform/core/pull/4795

[chalasr]

Thanks for the heads up.

Wouldn't this just annoy people with deprecations in logs when it's not possible to resolve them?

To answer this one: no, this won't lead to any deprecation notice in logs neither in core nor for end users, as long as the property is not extended (and if it is, that's ok, better get a resolvable notice than a BC break).

[alanpoulain]

Thanks Robin.