Fixing DisplayTest for VRR display VRR displays might have multiple modes differ only by vsync - switching between them will be transparent for apps Also VRR displays might have synthetic modes- that only limit render rate Bug: b/353140052 Test: atest DisplayTest#testModeSwitchOnPrimaryDisplay Flag: EXEMPT bugfix Change-Id: I02eed4a2f0a11b2d048af36af1ac929f91a12d93