Because every version of rongcloud_im_wrapper_plugin from path depends on js ^0.6.4 and image_cropper_for_web >=4.0.0 depends on js ^0.7.1, rongcloud_im_wrapper_plugin from path is incompatible with
image_cropper_for_web >=4.0.0.
And because image_cropper >=6.0.0 depends on image_cropper_for_web ^4.0.0, rongcloud_im_wrapper_plugin from path is incompatible with image_cropper >=6.0.0.
So, because expert_planet depends on both image_cropper ^6.0.0 and rongcloud_im_wrapper_plugin from path, version solving failed.
You can try the following suggestion to make the pubspec resolve:
* Consider downgrading your constraint on image_cropper: flutter pub add image_cropper:^5.0.1