Remove Vue set for vue 3 migration from protected environments

What does this MR do and why?

Describe in detail what your merge request does and why.

This MR partially resolves #452467 (closed)

What was cleaned up from epic:

1. Remove Vue.set

Vue set is no longer supported in VUE 3

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

NO VISUAL CHANGES

How to set up and validate locally

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

1. Checkout branch
2. Run test locally
3. Or just check in pipeline
4. Run it also with VUE_VERSION=3 yarn jest --watch 

You can check via UI

1. Go to project
2. Settings -> CI/CD
3. Protected environments
4. Try to protect/unprotect environment

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

ee/app/assets/javascripts/protected_environments/store/edit/mutations.js

-import Vue from 'vue';
 import * as types from './mutation_types';
 
 export const mutations = {
@@ -31,15 +30,21 @@ export const mutations = {
     state.loading = false;
   },
   [types.RECEIVE_MEMBER_SUCCESS](state, { type, rule, users }) {
-    Vue.set(state.usersForRules, `${type}-${rule.id}`, users);
+    state.usersForRules = {
+      ...state.usersForRules,
+      [`${type}-${rule.id}`]: users,
+    };
   },
   [types.REQUEST_UPDATE_PROTECTED_ENVIRONMENT](state) {
     state.loading = true;
   },
   [types.RECEIVE_UPDATE_PROTECTED_ENVIRONMENT_SUCCESS](state, environment) {
     const index = state.protectedEnvironments.findIndex((env) => env.name === environment.name);
-    Vue.set(state.protectedEnvironments, index, environment);
-    Vue.set(state.newDeployAccessLevelsForEnvironment, environment.name, []);
+    state.protectedEnvironments[index] = environment;
+    state.newDeployAccessLevelsForEnvironment = {
+      ...state.newDeployAccessLevelsForEnvironment,
+      [environment.name]: [],
+    };
 
     state.loading = false;
   },
@@ -50,14 +55,23 @@ export const mutations = {
     state.newDeployAccessLevelsForEnvironment[environment.name] = rules;
   },
   [types.EDIT_RULE](state, rule) {
-    Vue.set(state.editingRules, rule.id, { ...rule });
+    state.editingRules = {
+      ...state.editingRules,
+      [rule.id]: { ...rule },
+    };
   },
   [types.RECEIVE_RULE_UPDATED](state, rule) {
-    Vue.set(state.editingRules, rule.id, null);
+    state.editingRules = {
+      ...state.editingRules,
+      [rule.id]: null,
+    };
   },
   [types.DELETE_PROTECTED_ENVIRONMENT_SUCCESS](state, { name }) {
     state.protectedEnvironments = state.protectedEnvironments.filter((env) => env.name !== name);
-    Vue.set(state.newDeployAccessLevelsForEnvironment, name, []);
+    state.newDeployAccessLevelsForEnvironment = {
+      ...state.newDeployAccessLevelsForEnvironment,
+      [name]: [],
+    };
 
     state.loading = false;
   },