HDMI-CEC: Do not request active source if it is already cached

Check if HdmiControlService's buffer contains <Active Source> before
send <Request Active Source>. Added a new function in HdmiControlService
to getCecMessageWithOpcode.

Test: atest HdmiCecLocalDeviceTvTest
Bug: b/383941201
Flag: EXEMPT bugfix only
Change-Id: I929b470e0ae7a7715f67550afbc6f040c33812c8