Secure properties message is shown as ERROR when it should be a WARN

[afelisatti]

Version used
1.2.0

Describe the bug
When a secure properties config is migrated, since in Mule 4 those properties are distinguished with a secure prefix a report entry is generated explaining that the prefix should be added. However, this is an ERROR level report which makes users believe something went wrong with the migration. Additionally, the message does not seem to be clear enough for people to understand the action they should take.

Expected Behavior
The report entry is clear enough for users to understand they need to change their app and how.

Actual Behavior

               <!--Migration ERROR: Review uses of properties defined in the referenced 
                        file, and add the 'secure' prefix to them. -->
                <!-- For more information refer to: -->
                <!-- * https://docs.mulesoft.com/mule-runtime/4.3/migration-secure-properties-placeholder -->
                <!-- * https://docs.mulesoft.com/mule-runtime/4.3/secure-configuration-properties#usage -->

Reproducible Test Case
This is a report level issue which means it happens when reporting is enabled. If a mock is added to the unit tests, we could assert the message reported.