Guard code path to execute only if attribute exists

See merge request gitlab-org/gitlab!59114

The column `total_tuple_count` has only been introduced after the
migration helper had been used for the first time. That is, there is a
preceding migration using the helper. This migration and its schema
version does not know about the later column addition and hence the code
path fails.

We check if the attribute exists here, so we can safely work with it.

This is only needed in code paths that are already being used in
existing migrations.

See https://gitlab.com/gitlab-org/gitlab/-/issues/327447

Merge branch 'dreedy-use-find-verbiage-instead-of-get-verbiage-for-spec-helper-methods' into 'master'

Use find rather than get verbiage for spec helpers

See merge request gitlab-org/gitlab!59049

Add btn-icon class for GPG key delete button

See merge request gitlab-org/gitlab!57974

Improvements to the code quality badge in the MR diff file header

See merge request gitlab-org/gitlab!58833

Docs - Update 14.0 release date to June 22nd on maintenance policy page

See merge request gitlab-org/gitlab!58555

Copyedit docs for a project creation for Pages from template

See merge request gitlab-org/gitlab!59127

Update Gitaly version

See merge request gitlab-org/gitlab!59236

Improve performance of milestonish concern spec

See merge request gitlab-org/gitlab!58582

Be explicit about which props a Vue component takes

See merge request gitlab-org/gitlab!59048

Update Geo limitations in docs

See merge request gitlab-org/gitlab!54931

Track clicked templates for pipeline empty state experiment

See merge request gitlab-org/gitlab!58808

Update ESLint and related

See merge request gitlab-org/gitlab!58681

testing: Enable all Gitaly feature flags in CI

See merge request gitlab-org/gitlab!52308

Support `per_repository` elector's health check failure message

See merge request gitlab-org/gitlab!59116

Update metric definition under verify testing group

See merge request gitlab-org/gitlab!59028

Remove some ci_workflow_rules_variables FF checks

See merge request gitlab-org/gitlab!58777

Add pagination for VSA records

See merge request gitlab-org/gitlab!57843

Change loading, remove async on new graph

See merge request gitlab-org/gitlab!59187

Due date issue sidebar widget [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!58621

Optimize issuable updates

See merge request gitlab-org/gitlab!58114

- list each of the props that are gathered from the `dataset`
- also, we don't need to overcomplicate the specs by nesting `props`
  within an options object if the only option we ever use is `props`

Replace ruby:2.5 with ruby:3.0 in CI docs

See merge request gitlab-org/gitlab!59232

[RUN-AS-IF-FOSS] Resolve "Add assignees widget to issue sidebar"

See merge request gitlab-org/gitlab!56742

Add glfilteredsearch to group boards

See merge request gitlab-org/gitlab!56787

Fix broken branch switch with similar names

See merge request gitlab-org/gitlab!57197

Highlight non-recursion of `artifacts:exclude` in `.gitlab-ci.yml` keyword documentation

See merge request gitlab-org/gitlab!59196