fix: introduce dedicated queries for workspaces and workspace agents metrics (#19786)

aid in differentiation between sources of calls to `GetWorkspaces` but introducing new queries for metrics specific use cases

---------

Signed-off-by: Callum Styan <callumstyan@gmail.com>

coderd/database/queries/workspaceagents.sql

@@ -365,3 +365,26 @@ WHERE
 	id = $1
 	AND parent_id IS NOT NULL
 	AND deleted = FALSE;
+
+-- name: GetWorkspaceAgentsForMetrics :many
+SELECT
+    w.id as workspace_id,
+    w.name as workspace_name,
+    u.username as owner_username,
+    t.name as template_name,
+    tv.name as template_version_name,
+    sqlc.embed(workspace_agents)
+FROM workspaces w
+JOIN users u ON w.owner_id = u.id
+JOIN templates t ON w.template_id = t.id
+JOIN workspace_builds wb ON w.id = wb.workspace_id
+LEFT JOIN template_versions tv ON wb.template_version_id = tv.id
+JOIN workspace_resources wr ON wb.job_id = wr.job_id
+JOIN workspace_agents ON wr.id = workspace_agents.resource_id
+WHERE w.deleted = false
+AND wb.build_number = (
+    SELECT MAX(wb2.build_number)
+    FROM workspace_builds wb2
+    WHERE wb2.workspace_id = w.id
+)
+AND workspace_agents.deleted = FALSE;