Group titles do not get passed to accessible announcements

When Groups are used to group options in the Select, these groupings are not announced to screen reader users. This is because the announcements screen reader users hear are controlled by the LiveRegion component, and no information about an option's Group is passed to that LiveRegion.

For example, when using the arrow keys to "focus" an option in a group, we would expect to hear something like "[option name], option, not selected, [group name], group" from screen readers. Instead, we don't hear any information about the group name or group role. Currently, there is no good way for React Select users to customize the LiveRegion content to change this read out unless we completely overwrite the LiveRegion content using ariaLiveMessages.

React Select should pass on Grouping information to the LiveRegion component so that it can be announced to screen reader users. Here is a codesandbox instance with an example of grouped options: https://codesandbox.io/p/devbox/react-select-v5-sandbox-forked-9zwtgv

Start at the LiveRegion component and trace how grouped options reach its announcements, using the ariaLiveMessages customization described in the issue as context. Verify the result with grouped options like those in the linked CodeSandbox: screen readers should announce the option name, selection state, group name, and group role without requiring users to replace the entire LiveRegion content.