Add linting for Vue 2 delete api for specs

What does this MR do and why?

Add linting for Vue 2 delete api for specs

• mirror changes for non-spec files
• handle nested call of $delete from wrapper.vm.$delete()

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

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After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Apply the following patch

diff --git a/ee/spec/frontend/security_orchestration/components/policies/list_component_spec.js b/ee/spec/frontend/security_orchestration/components/policies/list_component_spec.js
index 154246482453..9de54bfba728 100644
--- a/ee/spec/frontend/security_orchestration/components/policies/list_component_spec.js
+++ b/ee/spec/frontend/security_orchestration/components/policies/list_component_spec.js
@@ -412,6 +412,10 @@ describe('List component', () => {
       });
 
       it('displays inherited scan execution policies', () => {
+        this.$delete();
+        wrapper.vm.$delete();
+        Vue.delete();
+        unwrappedVm.$delete();
         expect(trimText(findPolicyTypeCells().at(0).text())).toBe(
           POLICY_TYPE_FILTER_OPTIONS.SCAN_EXECUTION.text,
         );

1. Run node scripts/frontend/eslint.js ee/spec/frontend/security_orchestration/components/policies/list_component_spec.js
2. Verify errors appear