service/time: Add virtual destructors where applicable

Many of these implementations are used to implement a polymorphic
interface. While not directly used polymorphically, this prevents
virtual destruction from ever becoming an issue.

src/core/hle/service/time/steady_clock_core.h

@@ -16,6 +16,7 @@ namespace Service::Time::Clock {
 class SteadyClockCore {
 public:
     SteadyClockCore() = default;
+    virtual ~SteadyClockCore() = default;
 
     const Common::UUID& GetClockSourceId() const {
         return clock_source_id;

src/core/hle/service/time/system_clock_context_update_callback.h

@@ -20,7 +20,7 @@ namespace Service::Time::Clock {
 class SystemClockContextUpdateCallback {
 public:
     SystemClockContextUpdateCallback();
-    ~SystemClockContextUpdateCallback();
+    virtual ~SystemClockContextUpdateCallback();
 
     bool NeedUpdate(const SystemClockContext& value) const;
 

src/core/hle/service/time/system_clock_core.h

@@ -22,7 +22,7 @@ class SystemClockContextUpdateCallback;
 class SystemClockCore {
 public:
     explicit SystemClockCore(SteadyClockCore& steady_clock_core);
-    ~SystemClockCore();
+    virtual ~SystemClockCore();
 
     SteadyClockCore& GetSteadyClockCore() const {
         return steady_clock_core;