fix(ui5-flexible-column-layout): acc findings fixed

[PetyaMarkovaBogdanova]

2) FlexibleColumnLayout (7 failing)

• Missing/empty accessible names on arrow buttons (aria-label="").
• Nested interactive controls (interactive elements inside separator-like interactive containers).
• Invalid ARIA usage (aria-valuenow mismatch for the assigned role).

FlexibleColumnLayout	Arrow buttons have empty accessible name	aria-label empty string	Label is conditionally computed but resolves to empty in some layouts/states	Likely real	High	Always provide non-empty computed name or aria-labelledby fallback for each arrow action	Every visible arrow button has computable accessible name in all breakpoints
FlexibleColumnLayout	Nested interactive controls	interactive inside interactive host	Wrapper (separator/handle/button-like host) also made interactive while containing another interactive element	Mixed, scenario-sensitive	Medium	Keep one focusable interactive target; make container presentational if child is actionable	Tabbing lands once per control; no control inside another actionable host
FlexibleColumnLayout	aria-valuenow invalid for role	state-role mismatch	aria-valuenow applied to element whose role does not support range value properties	Likely real	High	Move range aria props to correct role (slider/progressbar/spinbutton etc.) or remove invalid prop	Role supports all assigned aria properties per ARIA spec

[ui5-webcomponents-bot]

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