Similar change is merged to widevine internal tool: ag/22824076
Some mandatory device info fields like manufacturer can be empty string
when returned from TEE on devices which have not been provisioned with
attestation IDs.
The extraction tool also needs to check for empty string in the
response, and if so, populates the field with Android property values.
Test: extracting device info from new Pixel EVT 1.1 and uploading
Bug: 276958001
Change-Id: I055ee0994d9dbbbf9c0c0875670a449a56a3e29e
8c0e7f2ba3