Remove bad recommendation

The documentation for gitlab_tag_protection states that one should set create_before_destroy = true to avoid the risk of ending up without tag protection if resource replacement fails.

This is a bad idea because because there can only be one tag protection per tag. Typically, the new replacement resource would fail to create due to conflict but due to the resource's automatic unprotection code it will succeed only for it to then be destroyed silently (leaving no tag protection).

Note: This recommendation was added in 9b7f761b / add allowed_to_create option to tag protection ... (!1549 - merged) but I was not able to find a rationale. Let me know if my reasoning is incorrect.