chore(azure): log the resolved MergeMethod for a given branch (#42847)

To aid with debugging, it would be useful to confirm what the resulting
method is, in both paths.

With help from GPT-4.1 to craft the enum-to-string conversion.

Co-authored-by: gpt-4.1 <jamie.tanna+github-copilot@mend.io>

Author: jamietanna

lib/modules/platform/azure/azure-helper.ts

@@ -167,15 +167,26 @@ export async function getMergeMethod(
 
   try {
     // TODO: fix me, wrong types
-    return Object.keys(policyConfigurations)
+    const method = Object.keys(policyConfigurations)
       .map(
         (p) =>
           GitPullRequestMergeStrategy[
             p.slice(5) as never
           ] as never as GitPullRequestMergeStrategy,
       )
       .find((p) => p)!;
+    logger.debug(
+      { policyConfigurations },
+      // TODO: types (#22198)
+      `getMergeMethod(branchRef=${branchRef!})=${GitPullRequestMergeStrategy[method]}`,
+    );
+    return method;
   } catch {
+    logger.debug(
+      { policyConfigurations },
+      // TODO: types (#22198)
+      `getMergeMethod(branchRef=${branchRef!})=NoFastForward, as an error occured`,
+    );
     return GitPullRequestMergeStrategy.NoFastForward;
   }
 }