When we check if MR is mergeable we also check the CI pipeline.
Since we are creating the pipeline asynchronously via
`MergeRequests::AfterCreateService`, there's a possible race
condition wherein the pipeline isn't created yet but we already
checked if MR is mergeable. That can result to inaccurate outcome.

To ensure that whenever we check if MR is mergeable, we introduced
a new internal state called `preparing`. When the MR is in this
state, it means it's still being prepared (e.g. creating a pipeline
) and it's not mergeable.

Once the preparation is finished, we mark the MR as unchecked so
we can check its mergeability when the user views the MR page.

Limit the changes for Danger

See merge request gitlab-org/gitlab!55154

Remove `.allow-wrap` css class

See merge request gitlab-org/gitlab!54810

Improve Metrics Dictionary docs

See merge request gitlab-org/gitlab!55086

Add edit value stream feature specs

See merge request gitlab-org/gitlab!54209

Add How to review for Product Intelligence changes to docs

See merge request gitlab-org/gitlab!55156

  - Add page for Product Intelligence review
  - Link from Usage Ping guide

Update Gitaly version

See merge request gitlab-org/gitlab!55341

[Feature flag] Rollout of "vue_notification_dropdown" [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!54422

Add descriptions to JobArtifactFileTypeEnum

See merge request gitlab-org/gitlab!55012

Disable repository mirroring for hard failures

See merge request gitlab-org/gitlab!54964

Merge branch 'philipcunningham-extend-services-to-take-optional-branch-when-running-an-on-demand-scan-322526' into 'master'

Extend DAST scan creation services to take optional branch

See merge request gitlab-org/gitlab!55129

Fix empty field in custom notification events modal

See merge request gitlab-org/gitlab!55313

Remove buy_storage_link Feature Flag [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!55246

Permanently enables purchase more storage button in usage quotas page

Use ProjectMember access_level_roles for invite members modal

See merge request gitlab-org/gitlab!55115

Rename merge request pipeline

See merge request gitlab-org/gitlab!55103

This commit renames our merge_request_pipeline as
merged_request_pipeline. This is part of our effort to consolidate
our naming with merge request pipeline.

Update references to "issuable_vue_app:change" to use constant

See merge request gitlab-org/gitlab!55311

Merge branch '300843-change-project-group-notes-es-searches-to-use-new-denormalized-fields' into 'master'

Change notes ES searches to use new denormalized fields

See merge request gitlab-org/gitlab!53294

Use new denormalized project visibility and project
feature permissions in the notes documents if the
ES migration has finished. The ES query supports
both before and after migration.

Update badge references

See merge request gitlab-org/gitlab!55031

Added "the following" to the example sentence

See merge request gitlab-org/gitlab!55331

Improve DAST introduction

See merge request gitlab-org/gitlab!54173

Update vale badge rule

See merge request gitlab-org/gitlab!55149

Add no MR Widget content case for release plugins

See merge request gitlab-org/gitlab!54992

Update test_coverage_visualization.md with C/C++ example

See merge request gitlab-org/gitlab!53407

Insert missing new lines to satisfy markdown lint checker.

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!55051

Only show 2FA badge to project maintainers and group owners

See merge request gitlab-org/gitlab!54646

Add btn-default class for the settings toggle button

See merge request gitlab-org/gitlab!54764