docs(spfx): 📝 deprecate online workbench#10816

andrewconnell wants to merge 1 commit intoSharePoint:mainSharePoint/sp-dev-docs:mainfrom

andrewconnell:content-update/spfx-v1-23-onlineworkbench-depandrewconnell/sp-dev-docs:content-update/spfx-v1-23-onlineworkbench-depCopy head branch name to clipboard