3566 [image_picker_for_web] Add doc comments to point out that some arguments aren’t supported on the web (cla: yes, p: image_picker, platform-web)

3573 [image_picker_platform_interface] Bump NNBD version to stable (cla: yes, nnbd, p: image_picker)

3579 [image_picker] NNBD stable (cla: yes, nnbd, p: image_picker, waiting for tree to go green)

3580 [image_picker] use nnbd version of deps to resolve ci failure (cla: yes, nnbd, p: image_picker)

3635 [image_picker_for_web] Bump version for NNBD stable (cla: yes, p: image_picker, platform-web, waiting for tree to go green)