[Logs AWS][Metrics AWS] Several dashboards are corrupt

Some dashboards installed by the AWS integrations are missing references matching kibanaSavedObjectMeta.searchSourceJSON.filter[0].meta.index from the pre-defined filters.

~This causes the Dashboard application to recognize this as a corrupt dashboard and the dashboard will be skipped in the search response and may not be listed in Dashboard listing pages and Dashboard pickers in modals (such as the Lens save modal).~ edit: this is fixed by https://github.com/elastic/kibana/pull/230313, but the paragraph below still applies.

In order for these dashboards to appear correctly in Kibana, a matching reference to the data view needs to be included in the `references` array. Without fixing the references, the dashboard will not apply the saved filters.

* [[Logs AWS] VPC Flow Log Overview](https://github.com/elastic/integrations/blob/0f7610104b561e73cac5cec35fa1d0ec94428252/packages/aws/kibana/dashboard/aws-15503340-4488-11ea-ad63-791a5dc86f10.json#L20)
* [[Logs AWS] S3 Server Access Log Overview](https://github.com/elastic/integrations/blob/08a290400371f0a67e50fb6e97765e3eb57f25f4/packages/aws/kibana/dashboard/aws-4746e000-bacd-11e9-9f70-1f7bda85a5eb.json#L14)
* [[Logs AWS] Security Hub Findings and Insights Overview](https://github.com/elastic/integrations/blob/08a290400371f0a67e50fb6e97765e3eb57f25f4/packages/aws/kibana/dashboard/aws-cc571400-dc61-11ec-a6e3-1bc5ab0aa1b4.json#L15)
* [[Logs AWS] Security Hub Findings Malware, Threat Intelligence Indicator and Network Path](https://github.com/elastic/integrations/blob/0f7610104b561e73cac5cec35fa1d0ec94428252/packages/aws/kibana/dashboard/aws-8fcf4c20-f7a3-11ec-aa7f-c173c0f9e267.json#L15)
* [[Metrics AWS] EC2 Overview](https://github.com/elastic/integrations/blob/08a290400371f0a67e50fb6e97765e3eb57f25f4/packages/aws/kibana/dashboard/aws-c5846400-f7fb-11e8-af03-c999c9dea608.json#L20)