Site Health: make sure layout tables have no semantics

[afercia]

The Site Health Info reports use HTML tables. See in the screenshot below:

During today's accessibility team meeting, we've discussed if these tables should be treated as data tables (and thus have proper table headers) or as simple layout tables.

Agreed for layout tables, as the table data is "relational in rows, it's just that it's not totally consistent data types that could use headers effectively."

In fact, the data in the right column can be paths, sizes, names, version numbers, URLs, etc. That makes nearly impossible to identify some headers text that can accurately represent the data type.

Also, agreed the most important thing is to communicate this data to assistive technologies in the simpler possible way (ensuring the content makes sense when linearized) rather than trying to identify what HTML semantics could be the most appropriate.

The accessibility team recommendation is to add an ARIA role="presentation" to the table element. For technologies that support ARIA, this actually removes any semantics from the table and its required children (all the cells).

Tests and support data available on powermapper:
​https://www.powermapper.com/tests/screen-readers/tables/table-role-presentation-layout-table/

[chetan200891]

Created initial patch to add an ARIA role="presentation" to the table element.

[chetan200891]

Last patch was showing changes of other ticket. so updated patch. :)

[afercia]

In 45075:

Accessibility: Make sure the Site Health layout tables are correctly linearized.

Adds role="presentation" to the <table> elements used in the Site Health reports.

Ideally, HTML tables should be used for tabular data. When tables are used for layout purposes, it's important to remove any native semantics so that assistive technologies can correctly announce the table content in a linearized fashion.

Props chetan200891.
Fixes #46725.