Fix _sgx_signed_enclave_transition
Fix _sgx_signed_enclave_transition

The split transition requires an extra [0] index on an attribute before
projecting a provider.

PiperOrigin-RevId: 294791312
Change-Id: I7844afdb14b0761dd17f8f80c6dadcbe19f32de9

google/asylo,google/asylo,google/asylo,google/asylo,google/asylo,google/asylo