fix: dgraph connection should ignore key for localhost

[mattjohnsonpint]

Description

When connecting to a dgraph instance on localhost, the key value should be ignored.

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[linear]

HYP-3129 Manifest with local dgraph and a empty key

[Copilot]

Pull Request Overview

This PR fixes the dgraph connection logic so that when connecting to a dgraph instance on localhost the key is ignored, and it ensures proper gRPC options are applied based on the target.

• Adjusts gRPC dial options to use insecure credentials for localhost
• Applies client TLS credentials and conditionally adds per-RPC credentials when a key is present for non-localhost connections
• Updates the CHANGELOG to document the fix

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
CHANGELOG.md	Updates the change log with the fix description
runtime/dgraphclient/registry.go	Modifies connection logic to ignore the key for localhost and properly handle TLS and authentication for non-localhost connections

Comments suppressed due to low confidence (1)

runtime/dgraphclient/registry.go:109

• [nitpick] Consider extracting the hostname from connection.GrpcTarget into a local variable to improve readability and avoid potential errors if the target string format changes.

if strings.Split(connection.GrpcTarget, ":")[0] == "localhost" {