Update tailscale.com dependency to latest version

[mostlygeek]

tsidp shows up in the admin console with a security warning:

The cause is that tsidp is using tailscale.com v1.86.5 and needs to be upgraded. Normally this would be easy BUT we're stuck on go v1.24 until govulncheck stops panicking due to jsonv2 (ref). Once that is fixed we will be unblocked to update to go 1.25 and the use the latest version of tailscale.com.

[batuozdemir]

In the meantime should we not use tsidp until it's updated?