Fix FBSDKLoginButton nonce property attributes

[kmcbride]

Thanks for proposing a pull request!

To help us review the request, please complete the following:

• sign contributor license agreement
• I've ensured that all existing tests pass and added tests (when/where necessary)
• I've updated the documentation (when/where necessary) and Changelog (when/where necessary)
• I've added the proper label to this pull request (e.g. bug for bug fixes)

Pull Request Details

The attributes for the nonce property of the FBSDKLoginButton are incorrect and lead to build errors.

In scenarios where the objc-property-assign-on-object-type flag is enabled and warnings are treated as errors, the build fails with: FBSDKLoginKit.framework/Headers/FBSDKLoginButton.h:109:1: 'assign' property of object type may become a dangling reference; consider using 'unsafe_unretained'

[facebook-github-bot]

Hi @kmcbride!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Facebook open source project. Thanks!

[facebook-github-bot]

@ppansy has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@ppansy merged this pull request in 9ce4507.