cluster: Fix for rm_stm holding up stm at startup

- This stm has a conditional in its last_stable_offset() method that
returns an invalid offset in the case it hasn't completed bootstrapping.

- The issue is that this bootstrap phase isn't considered finished after
bootstrapping from apply_snapshot(). This would cause other stms to
pause thinking the rm_stm had work to do at an offset at 0, causing
that other stm to timeout and fail processing of said event.

- Solution is simple, to set `_boostrap_committed_offset`within the
`apply_snapshot()` method

- Fixes: redpanda-data#11131

- Fixes: redpanda-data#11130

src/v/cluster/rm_stm.cc

@@ -2761,6 +2761,7 @@ rm_stm::apply_snapshot(stm_snapshot_header hdr, iobuf&& tx_ss_buf) {
         _log_state.lru_idempotent_pids.push_back(it->second);
     }
 
+    _bootstrap_committed_offset = data.offset;
     _last_snapshot_offset = data.offset;
     _insync_offset = data.offset;
 }