fix(GlPopover): properly align close button

mentioned in commit 19ba3cfd

mentioned in merge request gitlab!156175 (closed)

mentioned in merge request status-page!903

mentioned in merge request gitlab-org/editor-extensions/gitlab-jetbrains-plugin!570 (merged)

mentioned in merge request gitlab!156231 (merged)

mentioned in merge request gitlab!156343 (closed)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!3891 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!3892 (merged)

mentioned in merge request gitlab-org/frontend/playground/accessibility-scanner!39 (merged)

mentioned in merge request gitlab-org/frontend/pajamas-adoption-scanner!337 (merged)

mentioned in merge request gitlab-org/frontend/playground/accessibility-scanner!40 (merged)

mentioned in merge request gitlab-org/frontend/pajamas-adoption-scanner!338 (merged)

mentioned in merge request gitlab-org/frontend/playground/accessibility-scanner!42 (closed)