Drop accept from sentryctl socket filters

Now that we use x/sys/unix beyond https://golang.org/cl/313690 we always use
accept4 in place of accept.

PiperOrigin-RevId: 404265340

runsc/boot/filter/config.go

@@ -651,11 +651,6 @@ func controlServerFilters(fd int) seccomp.SyscallRules {
 				seccomp.EqualTo(fd),
 			},
 		},
-		unix.SYS_ACCEPT: []seccomp.Rule{
-			{
-				seccomp.EqualTo(fd),
-			},
-		},
 		unix.SYS_LISTEN: []seccomp.Rule{
 			{
 				seccomp.EqualTo(fd),