Fix used-before-assignment false positive for TYPE_CHECKING elif branch imports

doc/whatsnew/fragments/8437.bugfix

@@ -0,0 +1,4 @@
+Fix a ``used-before-assignment`` false positive when imports
+are made under the ``TYPE_CHECKING`` else if branch.
+
+Closes #8437

pylint/checkers/utils.py

@@ -2120,53 +2120,6 @@ def is_class_attr(name: str, klass: nodes.ClassDef) -> bool:
         return False
 
 
-def is_defined(name: str, node: nodes.NodeNG) -> bool:
-    """Searches for a tree node that defines the given variable name."""
-    is_defined_so_far = False
-
-    if isinstance(node, nodes.NamedExpr):
-        is_defined_so_far = node.target.name == name
-
-    if isinstance(node, (nodes.Import, nodes.ImportFrom)):
-        is_defined_so_far = any(node_name[0] == name for node_name in node.names)
-
-    if isinstance(node, nodes.With):
-        is_defined_so_far = any(
-            isinstance(item[1], nodes.AssignName) and item[1].name == name
-            for item in node.items
-        )
-
-    if isinstance(node, (nodes.ClassDef, nodes.FunctionDef)):
-        is_defined_so_far = node.name == name
-
-    if isinstance(node, nodes.AnnAssign):
-        is_defined_so_far = (
-            node.value
-            and isinstance(node.target, nodes.AssignName)
-            and node.target.name == name
-        )
-
-    if isinstance(node, nodes.Assign):
-        is_defined_so_far = any(
-            any(
-                (
-                    (
-                        isinstance(elt, nodes.Starred)
-                        and isinstance(elt.value, nodes.AssignName)
-                        and elt.value.name == name
-                    )
-                    or (isinstance(elt, nodes.AssignName) and elt.name == name)
-                )
-                for elt in get_all_elements(target)
-            )
-            for target in node.targets
-        )
-
-    return is_defined_so_far or any(
-        is_defined(name, child) for child in node.get_children()
-    )
-
-
 def get_inverse_comparator(op: str) -> str:
     """Returns the inverse comparator given a comparator.