Now, `caret_can_draw` will be validated when a condition that affects
the drawability of the `LineEdit`'s caret changes; `draw_caret` will
be toggled when the caret's visibility is toggled due to blink, and
`draw_caret` will be `false` when `caret_blink_enabled` is disabled.
Fix toggling `caret_blink_enabled` could cause caret to no longer be
displayed.
Fix opening the context menu causing caret to no longer appear.