[network] simplify peer connection backoff delay
[network] simplify peer connection backoff delay

Rather than have this formula to determine whether to delay less than
the max delay because there are less clients connected, we will simplify
this to just have one max delay for all.  Shorter max delay just because
there are less clients connected isn't necessary.

Closes: #4684
Approved by: davidiw

libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra