Fix: Degrade severity level for IPA-125 rules

Author: yelizhenden-mdb

tools/spectral/ipa/rulesets/IPA-125.yaml

@@ -36,7 +36,7 @@ rules:
         This is valid because there are exactly 2 mappings for 2 oneOf references, and all values match.
 
     message: '{{error}} https://mdb.link/mongodb-atlas-openapi-validation#xgen-IPA-125-oneOf-must-have-discriminator'
-    severity: error
+    severity: warn
     given: '$.components.schemas[*]'
     then:
       function: 'IPA125OneOfMustHaveDiscriminator'
@@ -84,7 +84,7 @@ rules:
       ```
 
     message: '{{error}} https://mdb.link/mongodb-atlas-openapi-validation#xgen-IPA-125-oneOf-no-base-types'
-    severity: error
+    severity: warn
     given: '$.components.schemas[*]'
     then:
       function: 'IPA125OneOfNoBaseTypes'