fault-monitor: fix clang warnings

Fix the following clang-warnings:
```
fault-monitor/operational-status-monitor.hpp:36:14: error: explicitly defaulted move assignment operator is implicitly deleted [clang-diagnostic-defaulted-function-deleted]
   36 |     Monitor& operator=(Monitor&&) = default;
      |              ^
fault-monitor/operational-status-monitor.hpp:56:23: note: move assignment operator of 'Monitor' is implicitly deleted because field 'bus' is of reference type 'sdbusplus::bus_t &' (aka 'sdbusplus::bus::bus &')
   56 |     sdbusplus::bus_t& bus;
      |                       ^
fault-monitor/operational-status-monitor.hpp:36:37: note: replace 'default' with 'delete'
   36 |     Monitor& operator=(Monitor&&) = default;
      |                                     ^~~~~~~
      |                                     delete
fault-monitor/operational-status-monitor.hpp:50:22: error: lambda capture 'this' is not used [clang-diagnostic-unused-lambda-capture]
   50 |                     [this](sdbusplus::message_t& m) { matchHandler(m); })
      |                      ^~~~
fault-monitor/operational-status-monitor.hpp:56:23: error: private field 'bus' is not used [clang-diagnostic-unused-private-field]
   56 |     sdbusplus::bus_t& bus;
      |                       ^
fault-monitor/operational-status-monitor.hpp:62:17: error: private field 'dBusHandler' is not used [clang-diagnostic-unused-private-field]
   62 |     DBusHandler dBusHandler;
      |                 ^
```

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia892c5e9c38d3174a18d2d3add8484b73b4a58db