DEV: Fix FakeLogger compat (#18562)

TaggedLogger requires these methods (see plugin backend failures in #18534)

spec/support/fake_logger.rb

@@ -16,22 +16,42 @@ class FakeLogger
     @debug << message
   end
 
+  def debug?
+    @level <= Logger::DEBUG
+  end
+
   def info(message = nil)
     @infos << message
   end
 
+  def info?
+    @level <= Logger::INFO
+  end
+
   def warn(message)
     @warnings << message
   end
 
+  def warn?
+    @level <= Logger::WARN
+  end
+
   def error(message)
     @errors << message
   end
 
+  def error?
+    @level <= Logger::ERROR
+  end
+
   def fatal(message)
     @fatals << message
   end
 
+  def fatal?
+    @level <= Logger::FATAL
+  end
+
   def formatter
   end
 end