[Tabs] Create design specs for Tabs overflow content

[Kritvi-bhatia17]

Description

Based on the related issue #21518 discussion, create design specifications for overflow content behavior across all Tabs variants.

Tasks

• Audit existing Tabs variants. Identify overflow scenarios and edge cases (long labels, many tabs, localization, etc.).
• Playback to the team, if required.
• Post considering any a11y considerations, create design specs for overflow content.
• Once flnalised
  • Update the current dev issue #21518 for updating the code.
  • Create the doc issue to reflect the changes.
  • Create the figma kit issue, if required.