Fix error with --import-mode=importlib and modules containing dataclasses or pickle (#7870)

Co-authored-by: Bruno Oliveira <nicoddemus@gmail.com>

Fixes #7856, fixes #7859

src/_pytest/python.py

@@ -577,7 +577,7 @@ class Module(nodes.File, PyCollector):
         # We assume we are only called once per module.
         importmode = self.config.getoption("--import-mode")
         try:
-            mod = import_path(self.path, mode=importmode)
+            mod = import_path(self.path, mode=importmode, root=self.config.rootpath)
         except SyntaxError as e:
             raise self.CollectError(
                 ExceptionInfo.from_current().getrepr(style="short")