[ Merge of https://widevine-internal-review.googlesource.com/c/cdm/+/178891/ ] Plugin to provide getPropertyByteArray("deviceSignedCsrPayload") which returns the signed CSR payload for device registration. It queries both BCC and device info to be set in plugin before calling this getPropertyByteArray("deviceSignedCsrPayload") method. The returned csr payload will be used by assemble the device CSR by the caller for device registration. Bug: 286556950 Test: build WV DRM plugin Change-Id: Ie592f53497f6d391ff232fd02bd4e66ca857e0e4