Error message bar overflows old boards and swimlanes sidebar

Summary

When an error message is flashed, it overflows the boards sidebar (both the old one and the new swimlane one)

Reported during the review of #47253 !47253 (comment 445549358)

Steps to reproduce

Perform any update that involves the backend using the sidebar.

Relevant logs and/or screenshots

added boards devopsplan frontend sectiondev typebug labels

mentioned in merge request !47253 (merged)

added to epic &4732 (closed)

unassigned @euko

changed title from Draft: Error message bar overflows old boards and swimlanes sidebar to Error message bar overflows old boards and swimlanes sidebar

changed the description

Setting label(s) groupproject management based on ~"Category:Boards".

added groupproject management label

mentioned in issue gitlab-org/quality/triage-reports#1987 (closed)

mentioned in issue gitlab-org/quality/triage-reports#2047 (closed)

mentioned in issue gitlab-org/quality/triage-reports#2143 (closed)

mentioned in issue gitlab-org/quality/triage-reports#2267 (closed)

added priority3 severity3 labels

mentioned in issue gitlab-org/quality/triage-reports#2338 (closed)

changed milestone to %Backlog

added [deprecated] Accepting merge requests label

added groupproduct planning label and removed groupproject management label

Verified that this still happens. This would be ~"good for new contributors"

added [deprecated] good for new contributors label

changed epic to &5596 (closed)

assigned to @fguibert

added workflowin dev label

mentioned in merge request !70030 (merged)

changed milestone to %14.3

added workflowin review label and removed workflowin dev label

added Hackathon label

removed [deprecated] Accepting merge requests label

added Deliverable label

added workflowverification label and removed workflowin review label

Fixed. Closing.

closed

mentioned in issue gl-retrospectives/plan#66 (closed)

added Category:Team Planning label