[website] update TabLine and TabPanel examples and a11y guides

[j-mnizhek]

Motivation and Context

We need to update:

• examples for TabLine and TabPanel, add tabpanels with content to all of them
• update documentation they have on accessibility

How has this been tested?

Manually.

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).
• Nice improve.

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly or it's not required.
• Unit tests are not broken.
• I have added changelog note to corresponding CHANGELOG.md file with planned publish date.
• I have added new unit tests on added of fixed functionality.

[sheila-semrush]

I'd replace this:

By default, the component switches content automatically when switching tabs.

With something like this:

By default, tabs are switched automatically when selected.

Also, do we want to make showing tooltips obligatory for truncated tab names? If yes, then maybe we should remove the tip about showing the tooltip and instead implement this behaviour out of the box.

BTW, thanks for nice examples! :3

[j-mnizhek]

Added small change from #1340 to example with disabled tab.

[j-mnizhek]

Moved these changes to #1368