[Slot] add nested slottable support

[jjenzz]

Description

This is inspired by #2197 and should resolve #3626, but I've made it backwards compatible and also improved the implementation of Slot slightly:

• Avoids rendering redundant extra Slot.SlotClone comps
• Replaces React.Children.only() error with a more intuitive warning
• Adds tests including thorough use-case examples in ssr-testing

[changeset-bot]

🦋 Changeset detected

Latest commit: 3a92e41

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 44 packages

Name	Type
@radix-ui/react-slot	Patch
@radix-ui/react-alert-dialog	Patch
@radix-ui/react-collection	Patch
@radix-ui/react-dialog	Patch
@radix-ui/react-menu	Patch
@radix-ui/react-popover	Patch
@radix-ui/react-primitive	Patch
radix-ui	Patch
@radix-ui/react-select	Patch
@radix-ui/react-tooltip	Patch
@radix-ui/react-accordion	Patch
@radix-ui/react-menubar	Patch
@radix-ui/react-navigation-menu	Patch
@radix-ui/react-one-time-password-field	Patch
@radix-ui/react-roving-focus	Patch
@radix-ui/react-slider	Patch
@radix-ui/react-toast	Patch
@radix-ui/react-context-menu	Patch
@radix-ui/react-dropdown-menu	Patch
@radix-ui/react-announce	Patch
@radix-ui/react-arrow	Patch
@radix-ui/react-aspect-ratio	Patch
@radix-ui/react-avatar	Patch
@radix-ui/react-checkbox	Patch
@radix-ui/react-collapsible	Patch
@radix-ui/react-dismissable-layer	Patch
@radix-ui/react-focus-scope	Patch
@radix-ui/react-form	Patch
@radix-ui/react-hover-card	Patch
@radix-ui/react-label	Patch
@radix-ui/react-password-toggle-field	Patch
@radix-ui/react-popper	Patch
@radix-ui/react-portal	Patch
@radix-ui/react-progress	Patch
@radix-ui/react-radio-group	Patch
@radix-ui/react-scroll-area	Patch
@radix-ui/react-separator	Patch
@radix-ui/react-switch	Patch
@radix-ui/react-tabs	Patch
@radix-ui/react-toggle-group	Patch
@radix-ui/react-toggle	Patch
@radix-ui/react-toolbar	Patch
@radix-ui/react-visually-hidden	Patch
@radix-ui/react-accessible-icon	Patch

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