Reset smart rename auto-suggestions to off for token billing (#83709)

With upcoming token-based billing, smart rename suggestions should be
off by default so automatic Copilot rename suggestions are not fetched
unless the user explicitly enables them.

Version the storage key for `CollapseSuggestionsPanel` (suffix `_v2`) so
that all users who previously had the toggle enabled are reset to the
default. Flip the default to `true` (panel collapsed -> auto suggestions
off). Users who want automatic suggestions will need to re-enable the
toggle.

Mirrors VSLanguageServerClient PR 728902 for the equivalent setting in
the LSP-based rename UI.

Fixes https://dev.azure.com/devdiv/DevDiv/_workitems/edit/2939559
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