fix(GlChartLegend): remove tooltips from labels of tabular legends

mentioned in commit 7b28c018

mentioned in merge request rpadovani/daintree!147 (merged)

mentioned in merge request gitlab!34433 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!1967 (merged)

mentioned in merge request status-page!87 (closed)

mentioned in merge request rpadovani/daintree!151 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!1971 (merged)

mentioned in merge request status-page!94 (merged)