Do not enforce UTF-8 in any forms

We already dropped support for IE 5-8, so we can drop the
workaround for these legacy web browsers.

`utf8=``%E2`%9C``%93` will be eliminated from URLs and forms.

Changelog: fixed
Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

app/assets/javascripts/filtered_search/filtered_search_manager.js

@@ -801,7 +801,7 @@ export default class FilteredSearchManager {
       paths.push(`search=${sanitized}`);
     }
 
-    let parameterizedUrl = `?scope=all&utf8=%E2%9C%93&${paths.join('&')}`;
+    let parameterizedUrl = `?scope=all&${paths.join('&')}`;
 
     if (this.anchor) {
       parameterizedUrl += `#${this.anchor}`;

config/initializers/action_view.rb

+# frozen_string_literal: true
+
+# This file was introduced during upgrading Rails from 5.2 to 6.0.
+# This file can be removed when `config.load_defaults 6.0` is introduced.
+
+# Don't force requests from old versions of IE to be UTF-8 encoded.
+Rails.application.config.action_view.default_enforce_utf8 = false

spec/frontend/filtered_search/filtered_search_manager_spec.js

@@ -185,7 +185,7 @@ describe('Filtered Search Manager', () => {
   });
 
   describe('search', () => {
-    const defaultParams = '?scope=all&utf8=%E2%9C%93';
+    const defaultParams = '?scope=all';
     const defaultState = '&state=opened';
 
     it('should search with a single word', (done) => {

spec/frontend/issues_list/components/issuables_list_app_spec.js

@@ -302,7 +302,6 @@ describe('Issuables list component', () => {
       my_reaction_emoji: 'airplane',
       scope: 'all',
       state: 'opened',
-      utf8: '✓',
       weight: '0',
       milestone: 'v3.0',
       labels: 'Aquapod,Astro',
@@ -312,7 +311,7 @@ describe('Issuables list component', () => {
 
     describe('when page is not present in params', () => {
       const query =
-        '?assignee_username=root&author_username=root&confidential=yes&label_name%5B%5D=Aquapod&label_name%5B%5D=Astro&milestone_title=v3.0&my_reaction_emoji=airplane&scope=all&sort=priority&state=opened&utf8=%E2%9C%93&weight=0&not[label_name][]=Afterpod&not[milestone_title][]=13';
+        '?assignee_username=root&author_username=root&confidential=yes&label_name%5B%5D=Aquapod&label_name%5B%5D=Astro&milestone_title=v3.0&my_reaction_emoji=airplane&scope=all&sort=priority&state=opened&weight=0&not[label_name][]=Afterpod&not[milestone_title][]=13';
 
       beforeEach(() => {
         setUrl(query);
@@ -356,7 +355,7 @@ describe('Issuables list component', () => {
 
     describe('when page is present in the param', () => {
       const query =
-        '?assignee_username=root&author_username=root&confidential=yes&label_name%5B%5D=Aquapod&label_name%5B%5D=Astro&milestone_title=v3.0&my_reaction_emoji=airplane&scope=all&sort=priority&state=opened&utf8=%E2%9C%93&weight=0&page=3';
+        '?assignee_username=root&author_username=root&confidential=yes&label_name%5B%5D=Aquapod&label_name%5B%5D=Astro&milestone_title=v3.0&my_reaction_emoji=airplane&scope=all&sort=priority&state=opened&weight=0&page=3';
 
       beforeEach(() => {
         setUrl(query);