build(opentelemetry): Fail agent shadow duplicates by default

Set the final agent shadowJar to fail on unexpected duplicate entries
while still allowing service descriptors to merge in the bootstrap and
inst paths. This keeps duplicate handling strict without breaking the
service file transformers Shadow still relies on.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adinauer

sentry-opentelemetry/sentry-opentelemetry-agent/build.gradle.kts

@@ -150,11 +150,10 @@ tasks {
 
     archiveClassifier.set("")
 
-    // INCLUDE is required so that mergeServiceFiles can see duplicates from both the
-    // upstream agent JAR and the isolated distro libs before they are deduplicated.
-    // Shadow 9.x enforces duplicatesStrategy before transformers run, so FAIL/EXCLUDE
-    // would prevent service file merging.
-    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+    duplicatesStrategy = DuplicatesStrategy.FAIL
+
+    filesMatching("META-INF/services/**") { duplicatesStrategy = DuplicatesStrategy.INCLUDE }
+    filesMatching("inst/META-INF/services/**") { duplicatesStrategy = DuplicatesStrategy.INCLUDE }
 
     // Shadow 9.x only applies relocations to service files handled by a ServiceFileTransformer.
     // We need two mergeServiceFiles calls: