Dialog.Title should accept a ref to allow focusing on modal open

[meatnordrink]

Is your feature request related to a problem? Please describe.
Currently, RNP modals are serious barriers to accessibility anywhere they are used, because they do not receive screen-reader focus when they open. This is a separate, and serious, issue. However, one workaround is to use React's AccessibilityInfo.setAccessibilityFocus() to manually set screen-reader focus to an element within the dialog, usually the dialog header, on dialog open.

To do this, you must get a reactTag to pass to setAccessibilityFocus(); findNodeHandle() returns a reactTag when you pass it a ref. SO, to be able to set focus to the title of a dialog, you need to be able to pass a ref to the title of the dialog.

Describe the solution you'd like
Therefore, Dialog.Title should accept a ref, so focus can be manually set to it when using setAccessibilityFocus().

Describe alternatives you've considered
The alternative is to either fix the underlying issue, or to not use RNP components for the dialog title. (Or, something janky like setting focus to a visually hidden title, and hiding the visual title from screen readers; but this type of approach is not best-practice.)

Additional context
I looked at opening a PR for this, and it will be more complicated than I'd hoped. DialogTitle needs to be wrapped in forwardRef; but then TextComponent, which can be either Text or Title, needs to also be able to take a ref, so both of those need to be wrapped in forwardRef as well.

I'd be happy to take this on if there was enthusiasm from the core team, and resources to review and approve it. But this would be a more involved PR than I've done for the project before, and would probably involve setting up the repo locally, enabling the linting etc. As the last couple tiny/simple PRs I've put up have been sitting now for 2 and 4 months respectively, I'd like to have a signal that the work will go somewhere before I jump in deeper.

But, if there are resources for approval and interest in it, it could be a good path for me to become more involved in supporting the project.