DEV: Rename with_secure_uploads? to should_secure_uploads? on Post (#26549)

This method name is a bit confusing; with_secure_uploads implies
it may return a block or something with the uploads of the post,
and has_secure_uploads implies that it's checking whether the post
is linked to any secure uploads.

should_secure_uploads? communicates the true intent of this method --
which is to say whether uploads attached to this post should be
secure or not.

plugins/chat/lib/chat/message_processor.rb

@@ -8,7 +8,7 @@ module Chat
     def initialize(chat_message, opts = {})
       @model = chat_message
       @previous_cooked = (chat_message.cooked || "").dup
-      @with_secure_uploads = false
+      @should_secure_uploads = false
       @size_cache = {}
       @opts = opts