Add approvalPolicies field and deprecate scanResultPolicies

What does this MR do and why?

This MR adds approvalPolicies field and deprecates scanResultPolicies. Deprecation issue: #439199

Field scanResultPolicies in GraphQL API is being renamed to approvalPolicies.

MR acceptance checklist

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Project	Group

How to set up and validate locally

1. Create a new group
2. Visit Secure -> Policies and create a group policy. Sample policy YAML:

   type: scan_result_policy
   name: Test policy
   description: ''
   enabled: true
   rules:
     - type: any_merge_request
       branch_type: protected
       commits: any
   actions:
     - type: require_approval
       approvals_required: 1
       role_approvers:
         - developer

3. Query GraphQL (/-/graphql-explorer):

   query groupApprovalPolicies {
       namespace: group(fullPath: "<group-path>") {
           id
           approvalPolicies(relationship: INHERITED) {
               nodes {
                   name
                   yaml
                   editPath
                   enabled
                   updatedAt
                   userApprovers {
                       id
                       name
                       webUrl
                   }
                   allGroupApprovers {
                       id
                       fullPath
                       webUrl
                   }
                   roleApprovers
               }
           }
       }
   }

4. Create a new project
5. Visit Secure -> Policies and create a project policy. Sample policy YAML:

   type: scan_result_policy
   name: Test policy
   description: ''
   enabled: true
   rules:
     - type: any_merge_request
       branch_type: protected
       commits: any
   actions:
     - type: require_approval
       approvals_required: 1
       role_approvers:
         - developer

6. Query GraphQL (/-/graphql-explorer):

   query projectApprovalPolicies {
       namespace: project(fullPath: "<project-path>") {
           id
           approvalPolicies(relationship: INHERITED) {
               nodes {
                   name
                   yaml
                   editPath
                   enabled
                   updatedAt
                   userApprovers {
                       id
                       name
                       webUrl
                   }
                   allGroupApprovers {
                       id
                       fullPath
                       webUrl
                   }
                   roleApprovers
               }
           }
       }
   }

Related to #439094 (closed)