Component/Extensions - Remove unnecessary cache clearing and prevent recursion

Component/Extensions - Remove unnecessary cache clearing and prevent recursion

Ensure the cached settings are updated _before_ post_change hooks are called for settings.

All the cache clears being performed by on_change hooks were redundant with what happens when
extensions are enabled/disabled so I removed it.

Also moved the extension install hook to use postInstall which should be more stable, and
added checks in onToggleComponents to prevent recursion.