Fix `track_memory_usage` on poetry-core 1.3.x installations (#14221)

* Fix `track_memory_usage` on poetry-core 1.3.x installations

The same kind of problem as discussed in #14085:

1. we defined an extra with an underscore
2. we look it up at runtime with an underscore
3. but poetry-core 1.3.x. installs it with a dash, causing (2) to fail.

Fix by using a dash everywhere.

* Changelog