GH-90732
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Validate extension JSON: Error: Field 'classes/TextServer/methods/shaped_text_get_word_breaks/arguments': size changed value in new API, from 2 to 3.
Validate extension JSON: Error: Field 'classes/TextServerExtension/methods/_shaped_text_get_word_breaks/arguments': size changed value in new API, from 2 to 3.

Added optional argument. Compatibility method registered.