Remove Legacy Commands that don't integrate with the Test Explorer

[mnoah1]

Is your feature request related to a problem? Please describe.
Now that the extension supports test run, debug, etc from the test explorer, as well as green arrow overlaid in the gutter that also tie to the test explorer, there are several existing commands that may cause confusion since they don't integrate with the test explorer. Examples includego.subtest.cursor, go.test.cursor, go.test.package, and others that tie to various functions in the goTest.ts file, but won't actually integrate with the contents of the test explorer.

Describe the solution you'd like
Remove/deprecate these functions, or disable the commands when test explorer is enabled.

Describe alternatives you've considered
Add additional logic provide access to the contents of the test explorer and consume the results after each run.

Additional context
N/A

[firelizzard18]

@h9jiang I believe we could set a context value when the test explorer (old or new) is enabled and then conditionally hide the commands from the command pallet. It may be better to only hide when Go Companion is present since it is a more complete replacement for the legacy system. WDYT?