Remove legacy "checkbox" settings option

[Half-Shot]

Based on #29280 (will adjust base branch once merged)
Split out from #29272

This removes a chunk of legacy code which used forceTooltipVisible to show some help text for a setting. This was only used by the identity server picker (#29280) and the font family setting. By making the font family setting use the toggle fields instead, this allows for a large chunk of code to be removed (and uses a more standard description field below an input, rather than a tooltip).

See diff

Checklist

• Tests written for new code (and old code if feasible).
• New or updated public/exported symbols have accurate TSDoc documentation.
• Linter and other CI checks pass.
• I have licensed the changes to Element by completing the Contributor License Agreement (CLA)

[t3chguy]

This seems to suggest moving everything from toggles to checkboxes, what changed?

[Half-Shot]

I get the feeling this was a choice made a quite a few design iterations ago. I'm assuming since the only bit of settings to ever use checkboxes was the author's own appearance settings. it wasn't ever expanded to the rest of the components.

If the plan is to still change over to checkboxes, we can check with design. However going one way or the other would reduce some overhead here.

[t3chguy]

Compound specifically supports both checkboxes and toggles so we should definitely query design which we should favour for what. @element-hq/design

[Half-Shot]

Closing in favor of a fresh PR #30169