HACKNET: spendHashes handles invalid targets inconsistently

[gmcew]

from #1782, ns.hacknet.spendHashes handles different invalid targets inconsistently, and additionally differently from the UI validity check logic.

To avoid making a breaking change with ns.hacknet.spendHashes (https://github.com/bitburner-official/bitburner-src/blob/d824cd4fa6692ca1e04173b892278b79587a88fb/src/Hacknet/HacknetHelpers.tsx), I don't touch it in this PR, but I want to hear your opinions about it:

When it sees a hashserver, it returns false without printing a warning.
Home and private servers are valid targets. It's inconsistent with how we determine the target in the UI. It's not exploitable, so it's not urgent.

[catloversg]

@d0sboots What do you think about this problem? Technically, fixing it is a breaking change for ns.hacknet.spendHashes, but I don't think that it's a big problem. Most players don't pass home or p-server to ns.hacknet.spendHashes.

[d0sboots]

I don't have a strong opinion on this matter.