bug(lambda): retain repository name for unknown git providers

[zyzzmohit]

What this PR does:

In pkg/app/piped/platformprovider/lambda/function.go, the FindArtifactVersions function attempts to parse the Git URL to generate a commit hyperlink for Lambda Source Code deployments. If it encounters a Git host it doesn't instantly recognize (like AWS CodeCommit or an internal Git server), it formerly fell into a default case that completely wiped out both the gitURL hyperlink AND the repoPath. This PR removes the line zeroing out repoPath, safely retaining the parsed repository path as the artifact name fallback when the Git provider's hyperlink format is visually unknown.

Why we need it:

Zeroing out the repoPath caused the ArtifactVersion.Name to become empty, resulting in completely blank artifact layers surfacing within the PipeCD web UI. By safely preserving the repoPath, PipeCD can correctly identify and display the source repository path during deployments even if it can't hyperlink the commit hash itself.

Which issue(s) this PR fixes:

Fixes #6666

Does this PR introduce a user-facing change?:
Yes.

• How are users affected by this change:

Users loading AWS Lambda configurations backed by unknown / self-hosted Git providers will now see their repository correctly displayed in the PipeCD UI.

• Is this breaking change: No.
• How to migrate (if breaking change): N/A