Eui: [Accessibility] Screen reader text for EuiBottomBar should refer to end of document

[peteharverson]

The screen reader text for the EuiBottomBar component currently uses visual language to refer to its location on the page There is a new menu opening with page level controls at the bottom of the document. Non-visual language should be used in place of 'bottom of the document'. end of document is suggested.

Originally filed as https://github.com/elastic/kibana/issues/31113

[theodesp]

Hey I can take this if it's OK.
I've located the EuiScreenReaderOnly with the above text. I change the text and the i18ntokens and update the test. Great job on this library.

[theodesp]

While I'm there I will try to convert the Bottom bar component to Typescript in a different PR

[snide]

@theodesp If you set up a PR we can give you review. Go for it!