fix(storage): skip unit tests under native profile in gapic-google-cloud-storage-v2

[nidhiii-27]

When building the java-storage folder or running GCS native presubmit checks in CI, the build fails with the following error:

[ERROR] There was an error in the forked process
[ERROR] TestEngine with ID 'junit-vintage' failed to discover tests
[ERROR] org.apache.maven.surefire.booter.SurefireBooterForkException: There was an error in the forked process
[ERROR] TestEngine with ID 'junit-vintage' failed to discover tests

1. The global parent profile native (defined in google-cloud-shared-config) triggers maven-surefire-plugin to perform test discovery on the JVM using the modern JUnit 5 Platform Launcher (JUnitPlatformProvider).
2. The generated unit tests in gapic-google-cloud-storage-v2 (such as StorageClientTest.java) are standard JUnit 4 tests.
3. For the JUnit 5 test launcher to discover and execute JUnit 4 tests, it requires junit-vintage-engine on the classpath. Since gapic-google-cloud-storage-v2 does not have this configured, the launcher throws a discovery crash.
4. While some handwritten client modules have custom canary tests configured, the GCS generated GAPIC module lacked a local native profile to skip native test compilation.

Added a local native profile to gapic-google-cloud-storage-v2/pom.xml to skip unit tests when compiling and running under native profiles.
The generated classes in gapic-google-cloud-storage-v2 are already fully tested natively under the main google-cloud-storage module. The main module compiles and runs a comprehensive gRPC native image canary test (com.google.cloud.storage.it.StorageNativeCanary), which directly exercises and validates the generated GAPIC client pathways at runtime.

[gemini-code-assist]

Code Review

This pull request adds a 'native' profile to the pom.xml file for the gapic-google-cloud-storage-v2 module. This profile is configured to skip tests, with a note indicating that native testing for this specific module is handled within the google-cloud-storage module. I have no feedback to provide as there were no review comments.