dubbo dubbo spi IOC not work

fix spi has just one impl and annotated @Adaptive on class,cause ioc invalid

What is the purpose of the change

When the interface class of spi has only one implementation and this implementation class is annotated by @Adaptive the IOC is invalid. you can see the test cases.

Brief changelog

supportExtensions is empty,but the adaptive class has value. so the inject shoud not null.

Verifying this change

Checklist

[x] Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
[ ] Each commit in the pull request should have a meaningful subject line and body.
[ ] Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
[ ] Check if is necessary to patch to Dubbo 3 if you are work on Dubbo 2.7
[ ] Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
[ ] Add some description to dubbo-website project if you are requesting to add a feature.
[ ] GitHub Actions works fine on your own branch.
[ ] If this contribution is large, please follow the Software Donation Guide.