Fix two low-hanging fruit compiler warnings

[jschmidt-icinga]

This fixes two compiler warnings that are spamming the compile log on my system.

build/icinga2/lib/icinga/notification-ti.hpp:21:24: warning: ‘virtual icinga::String icinga::NotificationNameComposer::MakeName(const icinga::String&, const icinga::Object::Ptr&) const’ can be marked override [-Wsuggest-override]
   21 |         virtual String MakeName(const String& shortName, const Object::Ptr& context) const;
      |                        ^~~~~~~~
build/icinga2/lib/icinga/notification-ti.hpp:22:33: warning: ‘virtual icinga::Dictionary::Ptr icinga::NotificationNameComposer::ParseName(const icinga::String&) const’ can be marked override [-Wsuggest-override]
   22 |         virtual Dictionary::Ptr ParseName(const String& name) const;
      |                                 ^~~~~~~~~

This one affects the generated files but as the warning suggests, they should easily be able to be marked as override without any negative effects.

icinga2/lib/icinga/notification.cpp: In member function ‘void icinga::Notification::BeginExecuteNotification(icinga::NotificationType, const icinga::CheckResult::Ptr&, bool, bool, const icinga::String&, const icinga::String&)’:
icinga2/lib/icinga/notification.cpp:475:54: warning: enumerated mismatch in conditional expression: ‘icinga::ServiceState’ vs ‘icinga::HostState’ [-Wenum-compare]
  475 |                         uint_fast8_t state = service ? service->GetState() : host->GetState();
      |                                              ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
icinga2/lib/icinga/notification.cpp:504:54: warning: enumerated mismatch in conditional expression: ‘icinga::ServiceState’ vs ‘icinga::HostState’ [-Wenum-compare]
  504 |                         uint_fast8_t state = service ? service->GetState() : host->GetState();
      |                                              ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This one stems from using the ternary operator to assign values of different types (HostState and ServiceState) to an integer or string. The solution is to first convert/cast the values, then assign them via the switch in the ternary operator.

[Al2Klimov]

I'm glad we're finally addressing compiler warnings! 🥳 Btw, here are more low-hanging fruits:

• #9728
• #9729
• #9730
• #9731