feat: reinitialize agents when a prebuilt workspace is claimed (#17475)

This pull request allows coder workspace agents to be reinitialized when
a prebuilt workspace is claimed by a user. This facilitates the transfer
of ownership between the anonymous prebuilds system user and the new
owner of the workspace.

Only a single agent per prebuilt workspace is supported for now, but
plumbing has already been done to facilitate the seamless transition to
multi-agent support.

---------

Signed-off-by: Danny Kopping <dannykopping@gmail.com>
Co-authored-by: Danny Kopping <dannykopping@gmail.com>

coderd/database/queries/workspaceagents.sql

@@ -253,6 +253,19 @@ WHERE
 			wb.workspace_id = @workspace_id :: uuid
 	);
 
+-- name: GetWorkspaceAgentsByWorkspaceAndBuildNumber :many
+SELECT
+	workspace_agents.*
+FROM
+	workspace_agents
+JOIN
+	workspace_resources ON workspace_agents.resource_id = workspace_resources.id
+JOIN
+	workspace_builds ON workspace_resources.job_id = workspace_builds.job_id
+WHERE
+	workspace_builds.workspace_id = @workspace_id :: uuid AND
+	workspace_builds.build_number = @build_number :: int;
+
 -- name: GetWorkspaceAgentAndLatestBuildByAuthToken :one
 SELECT
 	sqlc.embed(workspaces),