refactor(client): align ConfigGetAsync and FunctionListAsync with other GLIDE clients

[currantw]

Summary

ConfigGetAsync(ValkeyValue) and FunctionListAsync(FunctionListOptions?) in GlideClusterClient return multi-node ClusterValue<T> from AllPrimaries when no route is provided. All other GLIDE clients (Python, Java, Node) return a single value from one random node, relying on glide-core's default routing.

Description

Current C# behavior (no-route overloads):

• ConfigGetAsync(ValkeyValue) → routes to AllPrimaries, returns ClusterValue<KeyValuePair<string, string>[]>
• FunctionListAsync(FunctionListOptions?) → routes to AllPrimaries, returns ClusterValue<LibraryInfo[]>

Other GLIDE clients (Python, Java, Node):

• No-route versions rely on glide-core default (Random single node), return a plain single value
• Multi-node versions are only available when an explicit route is provided

The C# standalone client (GlideClient) already has the correct single-value signatures:

• ConfigGetAsync(ValkeyValue) → Task<KeyValuePair<string, string>[]>
• FunctionListAsync(FunctionListOptions?) → Task<LibraryInfo[]>

Proposed Solution

For both commands:

1. Remove the no-route multi-value method from IGlideClusterClient
2. Consolidate the single-value method into IBaseClient/BaseClient (no route, glide-core defaults to Random)
3. Retain the cluster-only with-route overload returning ClusterValue<T>

This aligns with other GLIDE clients and the existing pattern for ConfigGetAsync(IEnumerable<ValkeyValue>) which is already consolidated in BaseClient.

Effort & Severity Estimates

• Effort: medium
• Severity: low

Related

• task(client): consolidate redundant command implementations into BaseClient #462
• fix(client): ConfigSetAsync routes to AllPrimaries instead of AllNodes in cluster mode #492