This resolves a memory leak in the repo-server during plugin discovery caused by the connection not being closed.

Repo-Server Goroutines Leak

goroutine profile: total 1500
1458 @ 0x474eae 0x450a25 0x23d30ec 0x47d741
#	0x23d30eb	google.golang.org/grpc/internal/grpcsync.(*CallbackSerializer).run+0x10b	/go/pkg/mod/google.golang.org/grpc@v1.66.2/internal/grpcsync/callback_serializer.go:88

Repo-Server Goroutines Leak - Hard Refresh Applications x2

goroutine profile: total 4842
3138 @ 0x474eae 0x450a25 0x23d30ec 0x47d741
#	0x23d30eb	google.golang.org/grpc/internal/grpcsync.(*CallbackSerializer).run+0x10b	/go/pkg/mod/google.golang.org/grpc@v1.66.2/internal/grpcsync/callback_serializer.go:88

Fix Applied - Repo-Server Goroutines Leak - Hard Refresh Applications x2

Introduced by: #20196

Related improvement that would make this class of error harder to occur: #20217

This should be cherry-picked into the v2.13 release.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• The title of the PR conforms to the Toolchain Guide
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).
• My new feature complies with the feature status guidelines.
• I have added a brief description of why this PR is necessary and/or what this PR solves.
• Optional. My organization is added to USERS.md.
• Optional. For bug fixes, I've indicated what older releases this fix should be cherry-picked into (this may or may not happen depending on risk/complexity).