Fix for "poetry lock --no-update" so that dependencies with extras are not...

Fix for "poetry lock --no-update" so that dependencies with extras are not updated unnecessarily (#4618)

* Fix for "poetry lock --no-update" so that dependencies with extras are not updated unnecessarily

* None check instead of "or"

* Simplified logic (giving up possibility of early return when no matching version is found)

* Rename local variable for clarity