Implement resume workflow policy

What does this MR do and why?

**Summary by Duo**

This change adds a new "resume" permission for Duo workflows that allows users to restart workflows that are waiting for input. The permission is only granted to workflow owners when their workflow is in a specific "input required" state, meaning the workflow has paused and needs user interaction to continue. The implementation includes the necessary authorization rules, GraphQL API updates to expose the permission, and comprehensive tests to ensure it works correctly across different scenarios.

References

Relates to #594417 (closed)

How to set up and validate locally

1. Run this graphQL query

   query getAgentFlows(
     $projectPath: ID!
     $after: String
     $before: String
     $first: Int
     $last: Int
     $search: String
     $sort: DuoWorkflowsWorkflowSort
     $statusGroup: DuoWorkflowStatusGroup
     $type: String
   ) {
     project(fullPath: $projectPath) {
       id
       duoWorkflowWorkflows(
         projectPath: $projectPath
         first: $first
         after: $after
         last: $last
         before: $before
         search: $search
         sort: $sort
         statusGroup: $statusGroup
         type: $type
       ) {
         pageInfo {
           startCursor
           endCursor
           hasNextPage
           hasPreviousPage
         }
         edges {
           node {
             ...FlowFragment
           }
         }
       }
     }
   }
   
   fragment FlowFragment on DuoWorkflow {
     id
     status
     userPermissions {
       updateDuoWorkflow
       resumeDuoWorkflow
     }
   }

Input variables

{
  "projectPath": "gitlab-duo/test",
  "before": null,
  "after": null,
  "first": 20,
  "last": null,
  "sort": "UPDATED_DESC",
  "statusGroup": null,
  "type": null
}

2. You should see relevant resume workflows permissions when flow status is input_required and current_user is workflow owner.

MR acceptance checklist

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