Fix feature specs locally when host is not localhost

What does this merge request do and why?

This MR fixes an issue where feature specs sometimes fail locally because the hot module reloader address is not allowed by the CSP. This happens when the hostname is changed from localhost.

Fixes #1875 (closed)

How to set up and validate locally

1. Ensure your gdk.yml is using a hostname other than localhost.

2. Check out this merge request's branch.

3. Run gdk reconfigure to check if regenerating all configuration is successful.

   The below shows what will happen if your hostname is gdk.test (though I only ran the part of reconfigure that this MR affects):

   ➜  gdk git:(main) ✗ make gitlab/config/gitlab.yml   
   
   ℹ️  'gitlab/config/gitlab.yml' has incoming changes:
   -------------------------------------------------------------------------------------------------------------
   @@ -971,6 +971,10 @@ test:
        host: localhost
        port: 80
    
   +    content_security_policy:
   +      directives:
   +        connect_src: "'self' http://localhost:* ws://localhost:* wss://localhost:* ws://gdk.test:* wss://gdk.test:*"
   +
        # When you run tests we clone and set up gitlab-shell
        # In order to set it up correctly you need to specify
        # your system username you use to run GitLab
   
   -------------------------------------------------------------------------------------------------------------
   ⚠️  WARNING: 'gitlab/config/gitlab.yml' has been overwritten. To recover the previous version, run:
   
   cp -f '/Users/mkozonogitlab/Developer/gdk/.backups/gitlab__config__gitlab.yml.20230630120407' \
   '/Users/mkozonogitlab/Developer/gdk/gitlab/config/gitlab.yml'
   
   If you want to protect this file from being overwritten, see:
   https://gitlab.com/gitlab-org/gitlab-development-kit/-/blob/main/doc/configuration.md#overwriting-configuration-files
   -------------------------------------------------------------------------------------------------------------

4. In the gitlab directory, run an affected feature spec like bin/rspec ee/spec/features/projects/new_project_spec.rb:150

   It should succeed like this:

   ➜  gitlab git:(mk/add-3k-backup-runbook) ✗ bin/rspec ee/spec/features/projects/new_project_spec.rb:150
   [TEST PROF INFO] Spring detected
   Running via Spring preloader in process 24277
   Run options: include {:focus=>true, :locations=>{"./ee/spec/features/projects/new_project_spec.rb"=>[150]}}
   
   Test environment set up in 5.93115 seconds
   Starting the Capybara driver server...
   2023-06-30 11:58:01 WARN Selenium [:logger_info] Details on how to use and modify Selenium logger:
     https://selenium.dev/documentation/webdriver/troubleshooting/logging#ruby
   
   2023-06-30 11:58:01 WARN Selenium applicable driver not found; attempting to install with Selenium Manager
   Capybara starting Puma...
   * Version 6.3.0 , codename: Mugi No Toki Itaru
   * Min threads: 0, max threads: 4
   * Listening on unix:///var/folders/42/22jv0xts5730z1h5clsrr8wh0000gn/T/20230630-24277-v1k7mt
   .
   
   Finished in 25.66 seconds (files took 1.78 seconds to load)
   1 example, 0 failures
   
   [TEST PROF INFO] Time spent in factories: 00:00.618 (2.27% of total time)

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.