chore(ec2): remove egress rule warning when using allowFrom() (aws#14677

)

No need to warn the user if the `addEgressRule()` call came from a
`allowTo()` or ` allowFrom()` call because he can't do anything about
it.

Closes aws#13523


----

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

packages/@aws-cdk/aws-ec2/lib/security-group.ts

@@ -463,7 +463,9 @@ export class SecurityGroup extends SecurityGroupBase {
       // In the case of "allowAllOutbound", we don't add any more rules. There
       // is only one rule which allows all traffic and that subsumes any other
       // rule.
-      Annotations.of(this).addWarning('Ignoring Egress rule since \'allowAllOutbound\' is set to true; To add customize rules, set allowAllOutbound=false on the SecurityGroup');
+      if (!remoteRule) { // Warn only if addEgressRule() was explicitely called
+        Annotations.of(this).addWarning('Ignoring Egress rule since \'allowAllOutbound\' is set to true; To add customize rules, set allowAllOutbound=false on the SecurityGroup');
+      }
       return;
     } else {
       // Otherwise, if the bogus rule exists we can now remove it because the