chore(servicebus): regenerate api.metadata.yml with parser 0.3.31

The API consistency check regenerates with the latest
apiview-stub-generator from the azure-sdk feed, which has moved to 0.3.31,
while this package still carried the 0.3.30 stamp. parserVersion is a gated
field, so the check fails for any pull request touching azure-servicebus
until the stamp is refreshed.

api.md is unchanged: apiMdSha256 is identical before and after, so 0.3.31
produces byte-identical output. This is a version stamp only, with no API
surface change.

Refs: AB#38822503

Author: Pranjal Patel

sdk/servicebus/azure-servicebus/api.metadata.yml

@@ -1,3 +1,3 @@
 apiMdSha256: 68c237729c78165bea132f330a2e89519b2e6ba19373d40c48c55f09e8a994de
-parserVersion: 0.3.30
-pythonVersion: 3.12.10
+parserVersion: 0.3.31
+pythonVersion: 3.13.15