PYTHON-5431 Include assume role creds in backport task (#2418)

Author: blink1073

.evergreen/generated_configs/tasks.yml

@@ -128,6 +128,10 @@ tasks:
             - mongo-python-driver
             - ${github_commit}
           working_dir: src
+          include_expansions_in_env:
+            - AWS_ACCESS_KEY_ID
+            - AWS_SECRET_ACCESS_KEY
+            - AWS_SESSION_TOKEN
         type: test
 
   # Coverage report tests

.evergreen/scripts/generate_config.py

@@ -896,7 +896,8 @@ def create_backport_pr_tasks():
         "mongo-python-driver",
         "${github_commit}",
     ]
-    cmd = get_subprocess_exec(args=args)
+    include_expansions = ["AWS_ACCESS_KEY_ID", "AWS_SECRET_ACCESS_KEY", "AWS_SESSION_TOKEN"]
+    cmd = get_subprocess_exec(args=args, include_expansions_in_env=include_expansions)
     assume_func = FunctionCall(func="assume ec2 role")
     return [EvgTask(name=name, commands=[assume_func, cmd], allowed_requesters=["commit"])]