Since #17376, containerboot crashes on startup in k8s because state
encryption is enabled by default without first checking that it's
compatible with the selected state store. Make sure we only default
state encryption to enabled if it's not going to immediately clash with
other bits of tailscaled config.
Updates tailscale/corp#32909
Change-Id: I76c586772750d6da188cc97b647c6e0c1a8734f0
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>