MAINT-5011: Add log tag to LOG_UNHANDLED_EXCEPTION() log messages.

indra/llcommon/llexception.cpp

@@ -29,8 +29,8 @@ void log_unhandled_exception_(LLError::ELevel level,
 {
     // log same message but allow caller-specified severity level
     // lllog() is the macro underlying LL_ERRS(), LL_WARNS() et al.
-    lllog(level, false) << file << "(" << line << "): Unhandled exception caught in "
-                        << pretty_function;
+    lllog(level, false, "LLException")
+        << file << "(" << line << "): Unhandled exception caught in " << pretty_function;
     if (! context.empty())
     {
         LL_CONT << ": " << context;