Always updateRecording in ContentRecordingController#setContentRecordingSession

Race condition in DisplayManagerService meant that sometimes the boolean check gating updateRecording was unintentionally false, so now we always updateRecording to ensure that there is always an attempt to add new content to a freshly created DisplayContent used for mirroring.

Bug: 290911074
Test: atest CtsSurfaceControlTests:android.view.surfacecontrol.cts.SurfaceViewSyncTest#testSurfaceViewFixedSizeChanges --iterations 10
Test: atest CtsWindowManagerDeviceTestCases:android.server.wm.SurfaceSyncGroupContinuousTest#testSurfaceControlViewHostIPCSync_Slow --iterations 10
Test: atest WmTests:ContentRecorderTests
Test: atest WmTests:ContentRecordingControllerTests
Change-Id: I0db6f4fdb173fdab704f8cc93556ea65bc50d84c