Reference: #9954
Previously, these attributes were incorrectly trying to use `*time.Time` as the value input to `d.Set()`. These will return errors if error checking is performed, however our preferred convention of not performing error checking for "simple" attributes means that these silently would skip being added to the Terraform state with the refreshed API value.
The `tfproviderlint` `R004` check caught these previously though (which we would like to enable in the future but cannot until these and other failures are addressed):
```
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/data_source_aws_acmpca_certificate_authority.go:116:21: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/data_source_aws_acmpca_certificate_authority.go:117:22: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_acmpca_certificate_authority.go:362:21: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_acmpca_certificate_authority.go:363:22: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_emr_security_configuration.go:96:25: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_iam_service_linked_role.go:140:23: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_lambda_event_source_mapping.go:224:25: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_organizations_account.go:228:28: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_ssm_activation.go:159:27: R004: ResourceData.Set() incompatible value type: *time.Time
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_ssm_document.go:243:24: R004: ResourceData.Set() incompatible value type: *time.Time
```
Here we update each of these `d.Set()` calls with the appropriate RFC3339 timestamp value (our preferred format in lieu of other API standards).
The additional changes for `aws_ssm_activation` are to handle the API automatically setting a default value of 24 hours in advance. We do not want Terraform to return a difference in cases where the configuration does not have a value.
Output from acceptance testing:
```
--- PASS: TestAccDataSourceAwsAcmpcaCertificateAuthority_Basic (29.17s)
--- PASS: TestAccAwsAcmpcaCertificateAuthority_Basic (23.49s)
--- PASS: TestAccAWSEmrSecurityConfiguration_basic (18.22s)
--- PASS: TestAccAWSIAMServiceLinkedRole_basic (23.39s)
--- PASS: TestAccAWSLambdaEventSourceMapping_kinesis_basic (85.92s)
--- PASS: TestAccAWSLambdaEventSourceMapping_sqs_basic (134.73s)
--- PASS: TestAccAWSSSMActivation_expirationDate (24.95s)
--- PASS: TestAccAWSSSMActivation_basic (29.94s)
--- PASS: TestAccAWSSSMDocument_basic (21.52s)
```