htlcswitch: add new LinkFailureDisconnect action

In this commit, we add a new LinkFailureDisconnect action that'll be
used if we detect that the remote party hasn't sent a revoke and ack
when it actually should.

Before this commit, we would log our action, tear down the link, but
then not actually force a connection recycle, as we assumed that if the
TCP connection was actually stale, then the read/write timeout would
expire.

In practice this doesn't always seem to be the case, so we make a strong
action here to actually force a disconnection in hopes that either side
will reconnect and keep the good times rollin' 🕺.

docs/release-notes/release-notes-0.16.3.md

@@ -1,10 +1,10 @@
 # Release Notes
 
-## Mempool
+## Mempool Optimizations
 
 * Optimized [mempool
-management](https://github.com/lightningnetwork/lnd/pull/7681) to lower the CPU
-usage.
+  management](https://github.com/lightningnetwork/lnd/pull/7681) to lower the
+  CPU usage.
 
 ## Misc
 
@@ -12,7 +12,16 @@ usage.
   all macaroon DB root keys on `ChangePassword`/`GenerateNewRootKey`
   respectively.
 
+## Channel Link Bug Fix
+
+* If we detect the remote link is inactive, [we'll now tear down the
+  connection](https://github.com/lightningnetwork/lnd/pull/7711) in addition to
+  stopping the link's statemachine. If we're persistently connected with the
+  peer, then this'll force a reconnect, which may restart things and help avoid
+  certain force close scenarios.
+
 # Contributors (Alphabetical Order)
 
 * Elle Mouton
+* Olaoluwa Osuntokun
 * Yong Yu