ESID access for Delegated Cert Installer

Let the delegated cert installer read the Enrollment-specific ID, as
certificate management is tied to specific devices/enrollments.

Bug: 168627890
Test: atest com.android.cts.devicepolicy.MixedManagedProfileOwnerTest#testDelegatedCertInstaller
Change-Id: I6fd301d42342b8b6c94b27846dd859c507057d9e