feat(ui5-time-picker, ui5-datetime-picker): add keyboard/clock toggle… - #14216

Instead of relying on the initialFocus prop (which cannot resolve
elements inside shadow DOM via getElementById), focus is now applied
manually in onResponsivePopoverAfterOpen:
- clock mode → toggle button receives focus
- inputs mode → hours input receives focus (via TimeSelectionInputs
  focus delegation through data-sap-focus-ref)

Focus the toggle button unconditionally (when present) instead of
gating on showHeader or _useInputsMode, so focus is consistent
regardless of how the dialog was opened or which view is active.

…one only

Remove manual focus from onResponsivePopoverAfterOpen and restrict
the clock/keyboard toggle button to isPhone() only, so it does not
appear on narrow-desktop (phoneMode) or tablet views.

Move _openPickerInInputsMode from _onfocusin to _handleInputClick so
the dialog opens only on tap/click and not when VoiceOver or keyboard
navigation brings focus to the input field.

…log open

When the dialog opens on phone (showHeader=true): focus the first hours
input if in inputs mode, or the mode-toggle button if in clock mode.

…gle button

Add accessibleName ("Input view") and accessibleDescription ("Screen reader
users can use this view to enter a time.") to the phone mode-toggle button,
matching the ariaLabelledBy/ariaDescribedBy pattern from openui5 TimePicker.

…ode-toggle button

The description "Screen reader users can use this view to enter a time."
was ambiguous — it implied the clock view allows entry. Remove it and
keep only accessibleName="Input view" which correctly names the destination.

…le button

When in clock view: "Switch to Input view to enter hours, minutes, and seconds."
When in inputs view: "In this view you can enter hours, minutes, and seconds."

… descriptions

…de toggle

When toggling between clock and inputs view on phone, announce assertively:
- "Time input view displayed" when switching to inputs mode
- "Clock view" when switching back to clock mode
Matches the openui5 TimePicker InvisibleMessage.announce() behavior.

The accessible description is static in both views:
"Screen reader users can use this view to enter a time."
Only the tooltip changes dynamically per view.

…le button

Clock view: "Screen reader users should switch to Input view to enter a time."
Inputs view: "Screen reader users can use this view to enter a time."

…ui5 screenshots

Both clock and inputs view show the same static description:
"Screen reader users can use this view to enter a time."
Only the tooltip changes: "Switch to keyboard input" / "Switch to clock view"

…utton

Clock view: "Screen reader users should switch to Input view to enter a time."
Inputs view: "Screen reader users can use this view to enter a time."