Add expected_errors for extension aggregates v3

And remove some extra invalid params checking that
we didn't check in most of extensions. We can do
more strict checking when we have API input validation.

Fix bug 1214315
Partially implements bp v3-api-extension-versioning

Change-Id: I9c1f8265ea6e19e48cc2f8e747d04d3c3b66e55d
Merge "Add expected_errors for extension aggregates v3"