[Lens] Prepare the testing environment for improving A11y screen reader

[markov00]

Before improving the current accessibility descriptions in charts, we should prepare our environment by

• adding e2e tests for all charts to verify and validate the generated descriptions test(a11y): e2e baseline tests for a11y screen reader descriptions elastic-charts#2684
• refactor the a11y screen reader components to make them chart specific chore(refactor): refactors A11Y screen reader description generation into chart selector factories elastic-charts#2699

[elasticmachine]

Pinging @elastic/kibana-accessibility (Project:Accessibility)

[elasticmachine]

Pinging @elastic/kibana-visualizations (Team:Visualizations)