refactor(telemetry): drop the redundant unused-parameter casts in recordJobQueued

Both parameters already carry [[maybe_unused]], so the telemetry-disabled
arm needed nothing: the casts suppressed a warning that cannot fire. (void)enabled_
never suppressed anything either, because enabled_ is a member that isEnabled()
reads outside every #ifdef.

recordJobQueued was the only one of the seven record* stubs still carrying an
#else arm; it now has the same shape as recordJobStarted and the rest. The file
is left with no (void) casts and no #else at all.

src/xrpld/telemetry/MetricsRegistry.cpp

@@ -582,10 +582,6 @@ MetricsRegistry::recordJobQueued(
         1,
         {{label::jobType, std::string(jobType)},
          {label::handler, std::string(sanitiseHandler(jobName))}});
-#else
-    (void)jobType;
-    (void)jobName;
-    (void)enabled_;
 #endif
 }