Default value for interactive.execute should be True

[anthonykim1]

With the new REPL from Python extension merged, user has to explicitly set interactiveWindow.executeWithShiftEnter: false in their settings.json in order to execute via Enter Keypress when using interactive Native REPL.
They won't have to manually change this setting once the default value for interactiveWindow.execute is changed to True in core.

In order to provide closer experience to the traditional Python interactive interpreter experience (pressing enter would smartly execute or wait for more complete code), we should change the default value for interative.execute to be True.

Users who explicitly set their executeWithShiftEnter are respected at the current moment in a way that their settings are respected when using Python extension's native REPL to shift+enter or enter.

Related: #212051 microsoft/vscode-jupyter#15714