pageserver: update mgmt_api to use TenantShardId (#7313)

## Problem

The API client was written around the same time as some of the server
APIs changed from TenantId to TenantShardId

Closes: https://github.com/neondatabase/neon/issues/6154

## Summary of changes

- Refactor mgmt_api timeline_info and keyspace methods to use
TenantShardId to match the server

This doesn't make pagebench sharding aware, but it paves the way to do
so later.

pageserver/client/src/mgmt_api.rs

@@ -128,12 +128,12 @@ impl Client {
 
     pub async fn timeline_info(
         &self,
-        tenant_id: TenantId,
+        tenant_shard_id: TenantShardId,
         timeline_id: TimelineId,
         force_await_logical_size: ForceAwaitLogicalSize,
     ) -> Result<pageserver_api::models::TimelineInfo> {
         let uri = format!(
-            "{}/v1/tenant/{tenant_id}/timeline/{timeline_id}",
+            "{}/v1/tenant/{tenant_shard_id}/timeline/{timeline_id}",
             self.mgmt_api_endpoint
         );
 
@@ -151,11 +151,11 @@ impl Client {
 
     pub async fn keyspace(
         &self,
-        tenant_id: TenantId,
+        tenant_shard_id: TenantShardId,
         timeline_id: TimelineId,
     ) -> Result<pageserver_api::models::partitioning::Partitioning> {
         let uri = format!(
-            "{}/v1/tenant/{tenant_id}/timeline/{timeline_id}/keyspace",
+            "{}/v1/tenant/{tenant_shard_id}/timeline/{timeline_id}/keyspace",
             self.mgmt_api_endpoint
         );
         self.get(&uri)