Try to update import inplace on moving its target (PY-13870)

For example, a conditional import must remain under its condition
during the refatoring.

python/testData/refactoring/move/conditionalImport/after/src/mod1.py

@@ -0,0 +1,6 @@
+if True:
+    import pkgutil
+else:
+    from pkg1 import mod2 as pkgutil
+
+print(pkgutil)

python/testData/refactoring/move/conditionalImport/before/src/mod1.py

@@ -0,0 +1,6 @@
+if True:
+    import pkgutil
+else:
+    import mod2 as pkgutil
+
+print(pkgutil)