clarify r2 conflicting lifecycle rules

Author: harshal317

src/content/docs/r2/buckets/object-lifecycles.mdx

@@ -16,6 +16,7 @@ For example, you can create an object lifecycle rule to delete objects after 90
 - An object is no longer billable once it has been deleted.
 - Buckets have a default lifecycle rule to expire multipart uploads seven days after initiation.
 - When an object is transitioned from Standard storage to Infrequent Access storage, a [Class A operation](/r2/pricing/#class-a-operations) is incurred.
+- When object lifecycle rules conflict the cheapest action is taken -- expiration takes precedence over a storage tier transition.
 
 ## Configure lifecycle rules for your bucket