[receiver/prometheus] Correct changelog

Co-authored-by: George Krajcsovits <[email protected]>

Author: tinou98

.chloggen/prom-scrape-config-ta.yaml

@@ -4,10 +4,10 @@
 change_type: bug_fix
 
 # The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
-component: receiver/prometheus
+component: prometheusreceiver
 
 # A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
-note: Add 'fallback_scrape_protocol' to entries obtained through Target Allocator.
+note: Add 'fallback_scrape_protocol' to entries obtained through Target Allocator, unless already defined.
 
 # Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
 issues: [39672]