[CI] Bump mypy version 1.19.1 -> 1.20.2 (#44647)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tools/pre_commit/mypy.py

@@ -8,11 +8,9 @@ on files that have been changed. It groups files into different mypy calls
 based on their directory to avoid import following issues.
 
 Usage:
-    python tools/pre_commit/mypy.py <ci> <python_version> <changed_files...>
+    python tools/pre_commit/mypy.py <python_version> <changed_files...>
 
 Args:
-    ci: "1" if running in CI, "0" otherwise. In CI, follow_imports is set to
-        "silent" for the main group of files.
     python_version: Python version to use (e.g., "3.10") or "local" to use
         the local Python version.
     changed_files: List of changed files to check.
@@ -98,8 +96,8 @@ def mypy(
 
 
 def main():
-    python_version = sys.argv[2]
-    file_groups = group_files(sys.argv[3:])
+    python_version = sys.argv[1]
+    file_groups = group_files(sys.argv[2:])
 
     if python_version == "local":
         python_version = f"{sys.version_info.major}.{sys.version_info.minor}"