fix(saml): Set allowedAccounts info

[jmartinezfl]

With the changes introduced in #1744, the information related to the accounts the user has access to, is no longer available when authentication is performed using SAML. As a result, the allowedAccounts field appears as an empty list in the execution context.

With this fix, the information is set again, ensuring that the allowedAccounts parameter is correctly populated in the execution context when using SAML authentication.

[dbyron-sf]

@jmartinezfl please run $ ./gradlew spotlessApply, and add a test that fails without this fix.

[jasonmcintosh]

FYI: I THINK this is not needed. "allowedAccounts" would add http headers "X-SPINNAKER-ACCOUNTS" field. However, none of the internal services AT THIS POINT looks like they use this header anymore. As such, this shouldn't be needed. Will close this but if permissions ARE broken, please let us know we can open in github.com/spinnaker/spinnaker a new issue with this!