peer_store: Increase peer ban time until escapes banned threshold (#4031)

This is a tiny PR to increase the time a peer remains banned.

A peer is banned when the reputation drops below a threshold.
With every second, the peer reputation is exponentially decayed towards
zero.

For the previous setup:
- decaying to zero from (i32::MAX or i32::MIN) would take 948 seconds
(15mins 48seconds)
- from i32::MIN to escaping the banned threshold would take 10 seconds
This means we are decaying reputation a bit too aggressive and
misbehaving peers can misbehave again in 10 seconds.
Another side effect of this is that we have encountered multiple
warnings caused by a few misbehaving peers.

In the new setup:
- decaying to zero from (i32::MAX or i32::MIN) would take 3544 seconds
(59 minutes)
- from i32::MIN to escaping the banned threshold would take ~69 seconds

This is a followup of:
- https://github.com/paritytech/polkadot-sdk/pull/4000.

### Testing Done
- Created a misbehaving client with
[subp2p-explorer](https://github.com/lexnv/subp2p-explorer), the client
is banned for approx 69seconds until it is allowed to connect again.

cc @paritytech/networking

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Signed-off-by: Alexandru Vasile <[email protected]>