internal/rosa: remove global handles

These no longer serve any purpose.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/python.go

@@ -29,10 +29,13 @@ type PipHelper struct {
 
 var _ Helper = new(PipHelper)
 
+// pythonPyTest is used by [PipHelper] for automated testing.
+var pythonPyTest = H("python-pytest")
+
 // extra returns python, or pytest if defaults are assumed.
 func (attr *PipHelper) extra(int) P {
 	if attr == nil || (!attr.SkipCheck && attr.Check == "") {
-		return P{PythonPyTest}
+		return P{pythonPyTest}
 	}
 	return P{Python}
 }