[image_picker]: Add limit parameter in pickMultiImage

[behzodfaiziev]

This PR fixes the incorrect handling of the limit parameter in the pickMultiImage method of the image_picker package. Previously, the limit option was not respected across all platforms (Android, iOS, Web), allowing users to select more images than specified.

With this change, the image selection is now properly limited according to the provided limit value, ensuring that only the requested number of images are returned.

Fixes: flutter/flutter#170361

Pre-Review Checklist

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[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

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[stuartmorgan-g]

Please see https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changing-platform-interface-method-parameters to understand how we evolve platform interface APIs. Closing, as making a breaking change to the platform interface to add a parameter that we have already added using our documented, non-breaking process is not a change we would accept.