Fix milestone API specs in Ruby 2.1

See merge request !8555

[ci skip]

This is less invasive than the parent commit.

Ruby 2.3:
```
URI.parse('http://foo/bar?baz quux')
=> #<URI::HTTP http://foo/bar?baz%20quux>
```

Ruby 2.1:
```
URI.parse('http://foo/bar?baz quux')
URI::InvalidURIError: bad URI(is not URI?): http://foo/bar?baz quux
```

Add check for new path existence

Closes #26641

See merge request !8554

Copy <some text> to clipboard

See merge request !8535

Fixes the incoherent filtering by milestone in `/projects/:id/issues` and `/groups/:id/issues` endpoints

Closes #23194

See merge request !8457

Update gitlab-markup back to 1.5.1 in Gemfile

Closes #26627

See merge request !8550

Move dashboard help spinach test to rspec

See merge request !8436

Move dashboard group spinach test to rspec

See merge request !8434

Move dashboard archived projects spinach tests to rspec

See merge request !8431

Move dashboard active tab spinach test to rspec

See merge request !8423

Remove duplicate let in cycle_analytics_spec

See merge request !8422

Move admin users spinach tests to rspec

See merge request !8395

Refactor controller params

See merge request !8522

- Use IssuesFinder for the /issues API resouce
- Tests for iid filter in project issues API resource
- Tests for No Milestone filter in issues API resources
  The "No Milestone" case was not previously tested, and the `/issues`
  resource did not support the the `milestone` parameter.
- Return issues where all labels match from the issues and project issues
  API resources, like the group issues resource already does. See
  https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6825#note_17474533Signed-off-by: Rémy Coutable <remy@rymai.me>

Current filtering for "/projects/:id/issues" endpoint
returns no results for "No Milestone" query.

This PR introduces fix by copying filtering from "/groups/:id/issues"
which works as expected.

Use ReactiveCaching to update external CI status asynchronously

See https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2055

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Fixes pipeline status cell is too wide by adding missing classes in table head cells

Closes #26615

See merge request !8549

Signed-off-by: Rémy Coutable <remy@rymai.me>

Add changelog for search-bar-first-iteration

See merge request !8546

Adds mr id to changelog

Remove redundant parentheses in TodosController spec

[ci skip]

See merge request !8548

Use configured git rather thans system git

See merge request !8460

Do not check for valid url for .gitlab-ci.yml

Closes #22970

See merge request !8451