fix: eventual consistency in vpc tests (#260)

Description of changes:
Increasing the update wait time for vpc resource tests. The initial wait 
time was determined when ec2 had fewer resources. The more resources 
the more we see eventual consistency.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: michaelhtm

test/e2e/tests/test_vpc.py

@@ -31,7 +31,7 @@
 
 CREATE_WAIT_AFTER_SECONDS = 10
 DELETE_WAIT_AFTER_SECONDS = 10
-MODIFY_WAIT_AFTER_SECONDS = 5
+MODIFY_WAIT_AFTER_SECONDS = 15
 
 def get_vpc_attribute(ec2_client, vpc_id: str, attribute_name: str) -> dict:
     return ec2_client.describe_vpc_attribute(Attribute=attribute_name, VpcId=vpc_id)
@@ -269,6 +269,7 @@ def test_update_disallow_default_security_group_rule(self, ec2_client, simple_vp
 
         time.sleep(CREATE_WAIT_AFTER_SECONDS)
 
+        k8s.wait_on_condition(ref, "ACK.ResourceSynced", "True", wait_periods=5)
         # Check VPC exists in AWS
         ec2_validator = EC2Validator(ec2_client)
         ec2_validator.assert_vpc(resource_id)